Anette Eleonora Gunnæs

• Ravuri, SyamSai; Wrobel, Pawel S.; Gorantla, Sandeep; Bazioti, Kalliopi; Sunding, Martin Fleissner & Lis, Krzysztof [Show all 11 contributors for this article] (2024). High yield and wide lateral size growth of α-Mo<inf>2</inf>C: exploring the boundaries of CVD growth of bare MXene analogues. Nanotechnology. ISSN 0957-4484. 35(15). doi: 10.1088/1361-6528/ad1c97.
• Rahman, Jamil Ur; Soltani, Nayereh; Sunding, Martin Fleissner; Løvvik, Ole Martin; Gunnæs, Anette Eleonora & Finstad, Terje Gunnar [Show all 7 contributors for this article] (2024). Deciphering the structure of a high entropy Heusler antimonide. Acta Materialia. ISSN 1359-6454.
• Kamoutsi, Helen; Haidemenopoulos, Gregory N.; Gunnæs, Anette Eleonora & Diplas, Spyridon (2023). Microstructure and Salt Fog Corrosion of Wrought Mg-Al-Zn and Mg-RE Alloys. Materials. ISSN 1996-1944. 16(3). doi: 10.3390/ma16031004. Full text in Research Archive
• Reiersen, Magnus; Gunnæs, Anette Eleonora; S. Azar, Amin; Diplas, Spyridon; Du, Qiang & M&#39;Hamdi, Mohammed (2023). Accelerated material development for laser powder-bed fusion using the arc melting process. IOP Conference Series: Materials Science and Engineering. ISSN 1757-8981. 1274. doi: 10.1088/1757-899X/1274/1/012014. Full text in Research Archive
• Strandbakke, Ragnar; Wragg, David Stephen; Sørby, Magnus Helgerud; Guzik, Matylda; Gunnæs, Anette Eleonora & Szpunar, Iga [Show all 12 contributors for this article] (2022). Structural properties of mixed conductor Ba1−xGd1−yLax+yCo2O6−δ. Dalton Transactions. ISSN 1477-9226. 51(48), p. 18667–18677. doi: 10.1039/d2dt02277j. Full text in Research Archive Show summary

  Ba1−xGd1−yLax+yCo2O6−δ (BGLC) compositions with large compositional ranges of Ba, Gd, and La have been characterised with respect to phase compositions, structure, and thermal and chemical expansion. The results show a system with large compositional flexibility, enabling tuning of functional properties and thermal and chemical expansion. We show anisotropic chemical expansion and detailed refinements of emerging phases as La is substituted for Ba and Gd. The dominating phase is the double perovskite structure Pmmm, which is A-site ordered along the c-axes and with O vacancy ordering along the b-axis in the Ln-layer. Phases emerging when substituting La for Ba are orthorhombic Ba-deficient Pbnm and cubic LaCoO3-based R[3 with combining macron]c. When La is almost completely substituted for Gd, the material can be stabilised in Pmmm, or cubic Pm[3 with combining macron]m, depending on thermal and atmospheric history. We list thermal expansion coefficients for x = 0–0.3, y = 0.2.

• Poulia, Anthoula; Larsen, Aleksander Amble; Graff, Joachim Seland; Diplas, Spyridon; Gunnæs, Anette Eleonora & Mikheenko, Pavlo (2022). Imaging Magnetic Domain Structure of a High Entropy Alloy: Effect of Applied Magnetic Field, 2022 IEEE 12th International Conference Nanomaterials: Applications & Properties (NAP). IEEE (Institute of Electrical and Electronics Engineers). ISSN 978-1-6654-8982-9. p. NMM01-1–NMM01-5. doi: 10.1109/NAP55339.2022.9934250. Show summary

  High-Entropy Alloys (HEAs) are recently introduced materials consisting of numerous—at least five—elements in nearly equal-atomic concentrations. Studying them, previously unexplored phase fields in multidimensional phase diagrams are now being explored. The HEA concept is based on a thermodynamic balance between mixing entropy and enthalpy, which defines values of several critical parameters that determine the formation of simple or complicated phases. Physical properties, like magnetism, are of great interest for these materials, even though they have not been extensively analyzed so far. Particularly, the exploration of the magnetic domain structure and its correlation with the micro- and nano-structural features of the materials is of high scientific value. In this work, we study the influence of the magnetic history on the alteration of the magnetic domain patterns in polycrystalline FeCoNiAl0.9Mn0.9 High Entropy Alloy (HEA). For the study, we introduce a combinatorial method of Electron Backscatter Diffraction and Magnetic Force Microscopy imaging, which reveals specific magnetic domain structures in the grains of different crystallographic orientations. It is found that in the HEA polycrystal, an increase of the applied magnetic field affects the formation of magnetic domains and leads to a transition from a labyrinth-like pattern to a dotted domain configuration, which is expressed differently in the differently oriented grains.

• Amundsen, Monika; Pike, Nicholas; Løvvik, Ole Martin; Almeida Carvalho, Patricia & Gunnæs, Anette Eleonora (2022). New structure and insight on the phase transition within the Cu-Pd-Sn system with 25 at. % Sn. Materialia. ISSN 2589-1529. 24, p. 1–6. doi: 10.1016/j.mtla.2022.101461. Full text in Research Archive
• Bazioti, Kalliopi; Løvvik, Ole Martin; Poulia, Anthoula; Almeida Carvalho, Patricia; S. Azar, Amin & Mikheenko, Pavlo [Show all 8 contributors for this article] (2022). Probing the structural evolution and its impact on magnetic properties of FeCoNi(AlMn)x high-entropy alloy at the nanoscale. Journal of Alloys and Compounds. ISSN 0925-8388. 910, p. 1–12. doi: 10.1016/j.jallcom.2022.164724. Full text in Research Archive Show summary

  We report the first nanoscale investigation of FeCoNi(AlMn)x high-entropy alloys (HEAs) processed by laser metal deposition. The structural evolution of the alloy upon chemical composition variation (0.2 ≤ x ≤ 1.5) was investigated by combining imaging and spectroscopies in (scanning) transmission electron microscopy (S)TEM with density functional theory (DFT). A gradual change from a face-centered cubic (FCC) towards an ordered full-Heusler (L21) phase by increasing the Al and Mn contents was observed. Direct imaging and atomic-scale calculations revealed a nanoscale interplay between B2 and L21 ordered structures for x = 1.5, wherein the latter, Al and Mn occupy two different Wyckoff sites. By decreasing x, the FCC phase dominates exhibiting intense phase separation tendency, ordering phenomena, and nano-precipitation. Although not chemically discriminated, plasmon-peak splitting in low-loss electron energy loss spectra revealed the presence of two valence electron densities within the FCC phase. Lorentz TEM showed that the ordered nano-precipitates and nano-sized grains with a structure based on a tripled FCC unit cell are pinning-sites for magnetic domain walls and dislocations. All alloy compositions exhibited soft-magnetic behavior with coercivity (Hc) values< 1000 A/m. The FeCoNi(AlMn)1.5 alloy with L21/B2 nanostructure showed the highest magnetization (Ms) with relatively low Hc, attributed to the large magnetic moment of Mn and the synergistic effect of Mn-Al according to DFT, whilst ordering does not impose a negative effect. Phase separation trends within the FCC phase seem to decrease the Ms however, the overall impact on the magnetic behavior is not intense, opening up for new avenues for tuning FeCoNiAlMn properties through chemically-designed phase decomposition regimes.

• Rahman, Jamil Ur; Almeida Carvalho, Patricia; Soltani, Nayereh; Schrade, Matthias; Gunnæs, Anette Eleonora & Finstad, Terje Gunnar (2022). Synthesis, microstructure, and thermoelectric properties of Sb-Based high entropy alloys. Intermetallics (Barking). ISSN 0966-9795. 143. doi: 10.1016/j.intermet.2022.107495. Full text in Research Archive Show summary

  In this paper, we explore the synthesis of new antimonide compounds based upon concepts of high entropy alloys (HEA). HEAs are usually multi-element (⪆5) alloys with near the equiatomic composition. They have been given very large attention due to their vast potential within many fields. We investigated the thermoelectric transport properties of antimony-based high entropy alloys. The observed electrical conductivity, Seebeck coefficient, and thermal conductivity were comparable to those of cutting-edge half-Heusler thermoelectric alloys. Alloys with different valence electron counts (VEC) were synthesized and correlated with measured electrical properties.

• Pop-Ghe, Patricia; Amundsen, Monika; Zamponi, Christiane; Gunnæs, Anette Eleonora & Quandt, Eckhard (2021). Direct observation of intermediate twinning in the phase transformations of ferroelectric potassium sodium niobate. Ceramics International. ISSN 0272-8842. 47(14), p. 20579–20585. doi: 10.1016/j.ceramint.2021.04.067.
• Larsen, Aleksander Amble; Poulia, Anthoula; S. Azar, Amin; Bazioti, Kalliopi; Almeida Carvalho, Patricia & Gunnæs, Anette Eleonora [Show all 9 contributors for this article] (2021). Identifying Magnetic Phases in Additively Manufactured High-Entropy Alloy FeCoNiAlxMnx, 2021 IEEE 10th International Conference on “Nanomaterials: Applications & Properties” (NAP – 2021). IEEE (Institute of Electrical and Electronics Engineers). ISSN 978-1-6654-3907-7. p. NMM03-1–NMM03-4. doi: 10.1109/NAP51885.2021.9568591. Full text in Research Archive Show summary

  High-Entropy Alloys are advanced technological materials composed of several (typically five) elements in nearly equal atomic concentration. By forming these alloys, previously unknown phase fields of multidimensional phase diagrams are explored. The large number of possible substitutions of constituent elements on crystal lattice sites justifies the dominant contribution of mixing entropy over enthalpy to the free energy reduction. This leads to the formation of phases, which otherwise could not be formed in alloys with fewer main alloying elements. Here we explore magnetic and compositional properties of a High-Entropy Alloy, namely FeCoNiAl x Mn x (0.05 ≤ x ≤ 3.08), composed of magnetic (Fe, Co, Ni) and non-magnetic elements (Al, Mn). By magnetic force microscopy of a selected area, it is observed that for intermediate to low Al and Mn contents, the alloy splits in two major crystallographic phases with different magnetic properties. Elemental maps of the same area were recorded with energy dispersive spectroscopy and scanning electron microscopy. Counterintuitively, it was found that the phase rich in non-magnetic Al has stronger magnetism than the phase rich in Fe. This work showcases possible applications of the here presented HEAs as soft magnetic materials in functional magnetic elements.

• de Ruiter, Lisa; Gunnæs, Anette Eleonora; Dysthe, Dag Kristian & Austrheim, Håkon Olaf (2021). Quartz dissolution associated with magnesium silicate hydrate cement precipitation. Solid Earth (SE). ISSN 1869-9510. 12(2), p. 389–404. doi: 10.5194/se-12-389-2021.
• Poulia, Anthoula; S. Azar, Amin; Schrade, M.; Graff, J.S.; Bazioti, Kalliopi & Gunnæs, Anette Eleonora [Show all 8 contributors for this article] (2021). Process–Structure–Property Relationship in FeCoNiAlxMnx Complex Concentrated Alloys Processed by Additive Manufacturing. Journal of materials engineering and performance (Print). ISSN 1059-9495. 30, p. 6961–6971. doi: 10.1007/s11665-021-06082-8. Full text in Research Archive Show summary

  Fourteen alloys of the FeCoNiAlxMnx system were processed by laser metal deposition (LMD). The feedstock was a weighted and proportional blend of the containing elemental powders, targeting the nominal alloy compositions. Prior to processing, the composition and particle characteristics of the feedstock were assessed. The microstructural features and crystal structures of all LMD processed materials were characterized with scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction, in both as-received and heat-treated conditions. Selected samples were investigated via scanning transmission electron microscopy and electron backscattered diffraction for further structural understanding. Hardness tests, under various indentation loads and dwelling times, were performed to assess the mechanical properties of the processed samples. The results showed a rise in hardness as Al and Mn contents increase. The variation of hardness with composition follows a reverse sigma-type curve, reflecting the microstructural evolution and grain size variations in the alloys. Based on the hardness data, we suggest a trained and validated predictive model, which can be used in alloy design for future developments.

• Poulia, Anthoula; S. Azar, Amin; Svec, Peter; Bazioti, Kalliopi; Belle, Branson & Gunnæs, Anette Eleonora [Show all 8 contributors for this article] (2020). Nanoscale Magnetic Properties of Additively Manufactured FeCoNiAlxMnx High-Entropy Alloys, 2020 IEEE 10th International Conference on “Nanomaterials: Applications & Properties” (NAP – 2020). IEEE (Institute of Electrical and Electronics Engineers). ISSN 978-1-7281-8506-4. p. 01NMM02-1–01NMM02-5. doi: 10.1109/NAP51477.2020.9309571. Full text in Research Archive Show summary

  Magnetic properties of High-Entropy Alloys based on the Fe-Co-Ni-Al-Mn system are reported. High-Entropy Alloys are cutting-edge technological materials containing five or more elements in relatively high concentrations (5–35 at.%) within one or several solid-state solutions. These solutions are stabilized at the nanometer scale due to the high contribution of the mixing entropy to the Gibbs free energy, which can overcome the enthalpic contribution. Two magnetic alloys are found in FeCoNiAlxMnx (1.6 at.%  x  7.8 at.%) samples processed by laser metal deposition. The magnetic techniques used to screen the materials were magneto-optical imaging and magnetic force microscopy. The former allows characterizing magnetic properties within the mm-μm scale, while the latter is efficient down to the nanometer scale. Magnetic screening confirms the importance of the nanostructure in defining magnetic properties of the alloys, and the trends in the magnetic behavior as a function of the alloy composition are revealed. The experimental results suggest that it is possible to form unique alloys, which may outperform conventional magnetic materials used in a variety of applications such as transformers, screening shields and wind power generators.

• Kalyva, Maria Evangelou; Sunding, Martin Fleissner; Gunnæs, Anette Eleonora; Diplas, Spyridon & Redekop, Evgeniy (2020). Correlation between surface chemistry and morphology of PtCu and Pt nanoparticles during oxidation-reduction cycle. Applied Surface Science. ISSN 0169-4332. 532, p. 1–6. doi: 10.1016/j.apsusc.2020.147369. Full text in Research Archive Show summary

  Process conditions during catalytic reactions induce significant changes in surface chemistry and structure of bi- (mono) metallic nanoparticles leading to their deactivation, and this can ultimately affect the reactions long-term performance. Here PtCu and Pt model nanoparticles are prepared by microwave synthesis and characterized by X-ray diffraction (XRD). Surface chemical and morphological changes of the nanoparticles during high-temperature oxidation and reduction treatments cycle are correlated by near in situ X-ray photoelectron spectroscopy (XPS) and ex situ transmission electron microscopy (TEM) - energy-dispersive X-ray spectroscopy (EDS) studies. At 300 °C the surface atomic composition of the PtCu nanoparticles switches reversibly upon the cycle and at the same time their morphology and composition are maintained. At 400 °C, the surface atomic composition does not fully restore and, while the shape is maintained, the size and composition are not. This occurs by a mechanism of Cu leaching out from the nanoparticles. These data delineate potential operating conditions for stable PtCu nanocatalysts.

• Gutterød, Emil Sebastian; Pulumati, S.H.; Kaur, Gurpreet; Lazzarini, Andrea; Solemsli, Bjørn Garding & Gunnæs, Anette Eleonora [Show all 13 contributors for this article] (2020). Influence of Defects and H2O on the Hydrogenation of CO2 to Methanol over Pt Nanoparticles in UiO-67 Metal-Organic Framework. Journal of the American Chemical Society. ISSN 0002-7863. 142(40), p. 17105–17118. doi: 10.1021/jacs.0c07153. Full text in Research Archive
• Wachowski, Sebastian Lech; Szpunar, Iga; Sørby, Magnus Helgerud; Mielewczyk-Gryń, Aleksandra; Balaguer, Maria & Ghica, Corneliu [Show all 12 contributors for this article] (2020). Structure and water uptake in BaLnCo2O6−δ (Ln = La, Pr, Nd, Sm, Gd, Tb and Dy). Acta Materialia. ISSN 1359-6454. 199, p. 297–310. doi: 10.1016/j.actamat.2020.08.018. Full text in Research Archive
• Gunnæs, Anette Eleonora; Tofan, Raluca; Berland, Kristian; Gorantla, Sandeep Madhukar; Storaas, Thomas Aarflot & Desissa, Temesgen Debelo [Show all 12 contributors for this article] (2020). Chemical stability of Ca3Co4−xO9+δ/CaMnO3−δ p–n junction for oxide-based thermoelectric generators. RSC Advances. ISSN 2046-2069. 10(9), p. 5026–5031. doi: 10.1039/c9ra07159h. Full text in Research Archive Show summary

  An all-oxide thermoelectric generator for high-temperature operation depends on a low electrical resistance of the direct p–n junction. Ca3Co4−xO9+δ and CaMnO3−δ exhibit p-type and n-type electronic conductivity, respectively, and the interface between these compounds is the material system investigated here. The effect of heat treatment (at 900 °C for 10 h in air) on the phase and element distribution within this p–n junction was characterized using advanced transmission electron microscopy combined with X-ray diffraction. The heat treatment resulted in counter diffusion of Ca, Mn and Co cations across the junction, and subsequent formation of a Ca3Co1+yMn1−yO6 interlayer, in addition to precipitation of Co-oxide, and accompanying diffusion and redistribution of Ca across the junction. The Co/Mn ratio in Ca3Co1+yMn1−yO6 varies and is close to 1 (y = 0) at the Ca3Co1+yMn1−yO6–CaMnO3−δ boundary. The existence of a wide homogeneity range of 0 ≤ y ≤ 1 for Ca3Co1+yMn1−yO6 is corroborated with density functional theory (DFT) calculations showing a small negative mixing energy in the whole range.

• Molino, Andrea; Holzinger, J.; Lukaszuk, Katarzyna Anna; Rojo-Gama, Daniel; Gunnæs, Anette Eleonora & Skibsted, J. [Show all 11 contributors for this article] (2019). Synthesis of ZSM-23 (MTT) zeolites with differentcrystal morphology and intergrowths: effects onthe catalytic performance in the conversion ofmethanol to hydrocarbons. Catalysis Science & Technology. ISSN 2044-4753. 9(23), p. 6782–6792. doi: 10.1039/c9cy01068h. Full text in Research Archive
• Hjelmeland, Trude Bjørgås; Bazioti, Kalliopi; Gunnæs, Anette Eleonora; Volkov, Y & Mikheenko, Pavlo (2019). Effect of colossal magnetoresistance material La0.67Ca0.33MnO3 on superconducting properties of YBa2Cu3O7-δ thin films. Journal of Magnetism and Magnetic Materials. ISSN 0304-8853. 487. doi: 10.1016/j.jmmm.2019.165335. Full text in Research Archive
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Almeida Carvalho, Patricia; Berland, Kristian & Sørby, Magnus Helgerud [Show all 9 contributors for this article] (2019). Long- and short-range structures of Ti1-xHfxNi1.0/1.1Sn half-Heusler compounds and their electric transport properties. CrysteEngComm. ISSN 1466-8033. 21, p. 3330–3342. doi: 10.1039/c9ce00046a. Full text in Research Archive
• Oyama, Kohei; Diplas, Spyridon; M'hamdi, Mohammed; Gunnæs, Anette Eleonora & S. Azar, Amin (2019). Heat source management in wire-arc additive manufacturing process for Al-Mg and Al-Si alloys. Additive Manufacturing. ISSN 2214-8604. 26, p. 180–192. doi: 10.1016/j.addma.2019.01.007. Full text in Research Archive Show summary

  Modelling of wire-arc additive manufacturing process is an effective way for adapting the optimum parameters as well as understanding and managing the sequences of layer-by-layer deposition. Some of these parameters such as toolpath, deposition intervals and heat source power play important roles in improving the process viability and cost efficiency. In this article, we have studied Al-5Mg, Al-3Si alloys as demonstrators, from both experimental and modelling perspectives, to benchmark different deposition parameters and provided guidelines for optimising the process conditions. Physical values such as total distortion and residual stress were selected as indicators for the manufacturability of the structure. The simulations were performed by Simufact Welding software, that is outfitted with the MARC solver and the experiments were executed in a robotic cell. We have introduced a method for optimising the process parameters based on the heat source power modification and selection of unique parameters for each deposition layer. This was performed by monitoring the evolution of the molten pool size and geometry when building a wall structure. The results suggest that achieving an uninterrupted deposition process entails modification of the heat input for each layer. Thus, a simple analytical method was proposed to estimate the heat input reduction coefficient for a wall structure as a function of molten pool geometry and the height at which, a new layer is being deposited. It was also shown that a generic selection of parameters for aluminium alloys may impair the eventual quality for some of the alloys due to their inherent physical properties such as high temperature flowability.

• Bundli, Silje; Dhak, Prasanta; Jensen, Martin; Gunnæs, Anette Eleonora; Nguyen, Phuong Dan & Fjellvåg, Helmer [Show all 7 contributors for this article] (2019). Controlled alloying of Pt-Rh nanoparticles by the polyol approach. Journal of Alloys and Compounds. ISSN 0925-8388. 779, p. 879–885. doi: 10.1016/j.jallcom.2018.11.301.
• Bergum, Kristin; Riise, Heine Nygard; Gorantla, Sandeep Madhukar; Lindberg, Per; Jensen, Ingvild Julie Thue & Gunnæs, Anette Eleonora [Show all 10 contributors for this article] (2018). Improving carrier transport in Cu2O thin films by rapid thermal annealing. Journal of Physics: Condensed Matter. ISSN 0953-8984. 30(7). doi: 10.1088/1361-648X/aaa5f4.
• Guzik, Matylda N.; Echevarria-Bonet, Cristina; Riktor, Marit Dalseth; Almeida Carvalho, Patricia; Gunnæs, Anette Eleonora & Sørby, Magnus Helgerud [Show all 7 contributors for this article] (2018). Half-Heusler phase formation and Ni atom distribution in M-Ni-Sn (M = Hf, Ti, Zr) systems. Acta Materialia. ISSN 1359-6454. 148, p. 216–224. doi: 10.1016/j.actamat.2018.01.019. Full text in Research Archive
• Lindberg, Per Filip; Gorantla, Sandeep Madhukar; Gunnæs, Anette Eleonora; Svensson, Bengt Gunnar & Monakhov, Edouard (2017). Electronic properties and morphology of copper oxide/n-type silicon heterostructures. Journal of Physics: Condensed Matter. ISSN 0953-8984. 29(31). doi: 10.1088/1361-648X/aa77bc.
• Jensen, Ingvild Julie Thue; Gorantla, Sandeep Madhukar; Løvvik, Ole Martin; Gan, Jiantuo; Nguyen, Phuong Dan & Monakhov, Edouard [Show all 9 contributors for this article] (2017). Interface phenomena in magnetron sputtered Cu2O/ZnO heterostructures. Journal of Physics: Condensed Matter. ISSN 0953-8984. 29(43). doi: 10.1088/1361-648X/aa8799. Full text in Research Archive
• Schrade, Matthias; Berland, Kristian; Eliassen, Simen Nut Hansen; Guzik, Matylda Natalia; Echevarria-Bonet, Cristina & Sørby, Magnus Helgerud [Show all 13 contributors for this article] (2017). The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X=Hf, Zr, Ti) half-Heusler alloys. Scientific Reports. ISSN 2045-2322. 7. doi: 10.1038/s41598-017-14013-8. Full text in Research Archive
• Gunnæs, Anette Eleonora; Gorantla, Sandeep Madhukar; Løvvik, Ole Martin; Gan, Jiantuo; Carvalho, Patricia & Svensson, Bengt Gunnar [Show all 10 contributors for this article] (2016). Epitaxial strain-induced growth of CuO at Cu2O/ZnO interfaces. Journal of Physical Chemistry C. ISSN 1932-7447. 120(41), p. 23552–23558. doi: 10.1021/acs.jpcc.6b07197. Show summary

  Cu2O/ZnO has been envisaged as a potential material system for the next generation thin film solar cells. So far, the experimental efforts to obtain conversion efficiencies close to the theoretically predicted value have failed. Combining aberration-corrected (scanning) transmission electron microscopy and density functional theory modelling, we have studied the interfaces between single crystal c-axis oriented ZnO and high-quality magnetron sputtered Cu2O films. Strikingly, our study shows that the first ~5 nm of the Cu-oxide films have the structure of the monoclinic CuO phase. The CuO layer is textured with the (111), (11¯1), (¯111), (1¯1 ¯1), (¯1 ¯11), (1¯11), (¯11¯1) and (100) planes parallel to the (0001) and (000¯1) ZnO interfaces. The ionic arrangement on these planes resembles the hexagonal arrangement of the ZnO interface and epitaxy exists across the interface. A continued epitaxial growth of [111] oriented Cu2O follows resulting in epitaxial 180o rotation twins in the Cu2O layer. For the case with the (100)CuO interfacial plane we have: (111)[1¯10]Cu2O II (100)[011]CuO II (0001)[11¯20]ZnO. Because of a closer lattice matching of CuO with ZnO and Cu2O, the total strain and energy is reduced compared to a pure (111)Cu2O II (0001)ZnO interface. The existence of CuO is anticipated to be a contributing factor for the low conversion efficiencies obtained experimentally.

• Gan, Jiantuo; Gorantla, Sandeep Madhukar; Riise, Heine Nygard; Fjellvåg, Øystein Slagtern; Diplas, Spyridon & Løvvik, Ole Martin [Show all 9 contributors for this article] (2016). Structural properties of Cu2O epitaxial films grown on c-axis single crystal ZnO by magnetron sputtering. Applied Physics Letters. ISSN 0003-6951. 108:152110(15), p. 1–5. doi: 10.1063/1.4945985. Show summary

  Epitaxial Cu2O films grown by reactive and ceramic radio frequency magnetron sputtering on single crystalline ZnO (0001) substrates are investigated. The films are grown on both O- and Zn-polar surface of the ZnO substrates. The Cu2O films exhibit a columnar growth manner apart from a ∼5 nm thick CuO interfacial layer. In comparison to the reactively sputtered Cu2O, the ceramic-sputtered films are less strained and appear to contain nanovoids. Irrespective of polarity, the Cu2O grown by reactive sputtering is observed to have (111)Cu2O||(0001)ZnO epitaxial relationship, but in the case of ceramic sputtering the films are found to show additional (110)Cu2O reflections when grown on O-polar surface. The observed CuO interfacial layer can be detrimental for the performance of Cu2O/ZnO heterojunction solar cells reported in the literature.

• Song, Xin; Valset, Kjetil; Graff, Joachim Seland; Thøgersen, Annett; Gunnæs, Anette Eleonora & Luxsacumar, Sivakanesar [Show all 8 contributors for this article] (2015). Nanostructuring of undoped ZnSb by Cryo-Milling. Journal of Electronic Materials. ISSN 0361-5235. 44(8), p. 2578–2584. doi: 10.1007/s11664-015-3708-6. Show summary

  We report the preparation of nanosized ZnSb powder by cryo-milling. The effect of cryo-milling then hot-pressing of undoped ZnSb was investigated and compared with that of room temperature ball-milling and hot-pressing under different temperature conditions. ZnSb is a semiconductor with favorable thermoelectric properties when doped. We used undoped ZnSb to study the effect of nanostructuring on lattice thermal conductivity, and with little contribution at room temperature from electronic thermal conductivity. Grain growth was observed to occur during hot-pressing, as observed by transmission electron microscopy and x-ray diffraction. The thermal conductivity was lower for cryo-milled samples than for room-temperature ball-milled samples. The thermal conductivity also depended on hot-pressing conditions. The thermal conductivity could be varied by a factor of two by adjusting the process conditions and could be less than a third that of single-crystal ZnSb.

• Nguyen, Phuong Dan; Gunnæs, Anette Eleonora; Sunding, Martin Fleissner & Olsen, Arne (2014). Heterogeneous nucleation and growth of CrSi2 in sputtered thin films of silicon/silicon nitride. Thin Solid Films. ISSN 0040-6090. 556, p. 200–205. doi: 10.1016/j.tsf.2014.01.080.
• Hage, Fredrik Sydow; Kepaptsoglou, Despoina Maria; Seabourne, Ché Royce; Ramasse, Quintim M.; Scott, Andrew J. & Prytz, Øystein [Show all 8 contributors for this article] (2014). Dielectric response of pentagonal defects in multilayer graphene nano-cones. Nanoscale. ISSN 2040-3364. 6(3), p. 1833–1839. doi: 10.1039/c3nr05419e.
• Hage, Fredrik Sydow; Ramasse, Quentin; Kepaptsoglou, Despoina Maria; Prytz, Øystein; Gunnæs, Anette Eleonora & Helgesen, Geir [Show all 7 contributors for this article] (2013). Topologically induced confinement of collective modes in multilayer graphene nanocones measured by momentum-resolved STEM-VEELS. Physical Review B. Condensed Matter and Materials Physics. ISSN 1098-0121. 88(15). doi: 10.1103/PhysRevB.88.155408.
• Bleken, Bjørn Tore Lønstad; Wragg, David; Arstad, Bjørnar; Gunnæs, Anette Eleonora; Mouzon, Johanne & Helveg, Stig [Show all 12 contributors for this article] (2013). Unit cell thick nanosheets of zeolite H-ZSM-5: Structure and activity. Topics in catalysis. ISSN 1022-5528. 56(9-10), p. 558–566. doi: 10.1007/s11244-013-0010-9. Show summary

  Nanosheets of zeolite H-ZSM-5 were synthesized and characterized by X-ray diffraction, transmission electron microscopy (TEM), N2-physisorption, FT-IR spectroscopy, 27Al and 29Si MAS NMR spectroscopy in addition to catalytic testing in conversion of methanol to hydrocarbons (MTH). It was found that Rietveld analysis, involving anisotropic broadening parameters, gave average crystallite dimensions in good agreement with TEM images. The selectivities in MTH is intact in the mesoporous nanosheet H-ZSM-5 with the largest difference being a higher C3/C2 ratio compared to regular H-ZSM-5.

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• Rahman, Jamil Ur; Gunnæs, Anette Eleonora; Finstad, Terje Gunnar; Løvvik, Ole Martin & Almeida Carvalho, Patricia (2023). Structure of a high entropy Heusler antimonide.
• Bazioti, Kalliopi; Gorantla, Sandeep; Ravuri, SyamSai; Wrobel, Pawel S.; Sunding, Martin Fleissner & Sartori, Sabrina [Show all 9 contributors for this article] (2023). In situ and operando transmission electron microscopy: real-time nanoscale insights into emerging materials for batteries.
• Bazioti, Kalliopi; Gorantla, Sandeep; Ravuri, SyamSai; Wrobel, Pawel S.; Sunding, Martin Fleissner & Sartori, Sabrina [Show all 9 contributors for this article] (2023). In situ and operando transmission electron microscopy investigations of MXene-based anodes for Li-ion all-solid-state batteries.
• Bazioti, Kalliopi; Gorantla, Sandeep; Sunding, Martin Fleissner; Sartori, Sabrina; Diplas, Spyridon & Bachmatiuk, Alicja [Show all 7 contributors for this article] (2023). In situ and Operando Transmission Electron Microscopy investigations of novel 2D-based anodes for Li-ion all-solid-state batteries .
• Rahman, Jamil Ur; Sunding, Martin Fleissner; Løvvik, Ole Martin; Gunnæs, Anette Eleonora; Finstad, Terje Gunnar & Almeida Carvalho, Patricia (2023). Deciphering the structure of a high-entropy Heusler antimonide.
• Løvvik, Ole Martin; Rahman, Jamil Ur; Finstad, Terje Gunnar; Gunnæs, Anette Eleonora & Almeida Carvalho, Patricia (2022). Thermoelectric properties of multiple component (high entropy) silicides and antimonides.
• Løvvik, Ole Martin; Carvalho, Patricia A.; Stange, Marit Synnøve Sæverud; Sunding, Martin Fleissner; Rajput, Kalpna & Larsen, Aleksander Amble [Show all 9 contributors for this article] (2022). Elastocaloric cooling with TiNiCuZr alloys?
• Reiersen, Magnus; Gunnæs, Anette Eleonora; S. Azar, Amin; Diplas, Spyridon; Du, Qiang & M`hamdi, Mohammed (2022). Accelerated material development for laser powder-bed fusion using the arc melting process.
• Poulia, Anthoula; Larsen, Aleksander; Joachim Seland, Graff; Diplas, Spyros; Gunnæs, Anette Eleonora & Mikheenko, Pavlo (2022). Imaging Magnetic Domain Structure of a High Entropy Alloy: Effect of Applied Magnetic Field. Show summary

  High-Entropy Alloys (HEAs) are recently introduced materials consisting of numerous—at least five—elements in nearly equal-atomic concentrations. Studying them, previously unexplored phase fields in multidimensional phase diagrams are now being explored. The HEA concept is based on a thermodynamic balance between mixing entropy and enthalpy, which defines values of several critical parameters that determine the formation of simple or complicated phases. Physical properties, like magnetism, are of great interest for these materials, even though they have not been extensively analyzed so far. Particularly, the exploration of the magnetic domain structure and its correlation with the micro- and nano-structural features of the materials is of high scientific value. In this work, we study the influence of the magnetic history on the alteration of the magnetic domain patterns in polycrystalline FeCoNiAl0.9Mn0.9 High Entropy Alloy (HEA). For the study, we introduce a combinatorial method of Electron Backscatter Diffraction and Magnetic Force Microscopy imaging, which reveals specific magnetic domain structures in the grains of different crystallographic orientations. It is found that in the HEA polycrystal, an increase of the applied magnetic field affects the formation of magnetic domains and leads to a transition from a labyrinth-like pattern to a dotted domain configuration, which is expressed differently in the differently oriented grains.

• Bazioti, Kalliopi; Gorantla, Sandeep; Sunding, Martin Fleissner; Sartori, Sabrina; Diplas, Spyridon & Bachmatiuk, Alicja [Show all 7 contributors for this article] (2022). In situ and Operando Transmission Electron Microscopy investigations of MXenes for Li-ion all-solid-state batteries.
• Bazioti, Kalliopi; Gorantla, Sandeep; Sunding, Martin Fleissner; Sartori, Sabrina; Diplas, Spyridon & Bachmatiuk, Alicja [Show all 7 contributors for this article] (2022). Novel 2D-based anodes for Li-ion all-solid-state batteries.
• Pop-Ghe, Patricia; Amundsen, Monika; Zamponi, Christiane; Gunnæs, Anette Eleonora & Quandt, Eckhard (2021). Direct observation of intermediate twinning in the phase transformations of ferroelectric potassium sodium niobate.
• Poulia, Anthoula; S. Azar, Amin; Bazioti, Kalliopi; Gunnæs, Anette Eleonora; Mikheenko, Pavlo & Diplas, Spyridon (2021). Investigation of High Entropy Alloys via Magnetic Force Microscopy.
• Poulia, Anthoula; S. Azar, Amin; Bazioti, Kalliopi; Gunnæs, Anette Eleonora; Mikheenko, Pavlo & Diplas, Spyridon (2021). Additively manufactured FeCoNi(AlMn)x high entropy alloys: Mechanical and magnetic properties investigation.
• Poulia, Anthoula; S. Azar, Amin; Gunnæs, Anette Eleonora; Bazioti, Kalliopi; Mikheenko, Pavlo & Diplas, Spyridon (2021). Tailoring mechanical and magnetic properties of the FeCoNi(AlMn)x high entropy alloys via compositional alterations.
• Bazioti, Kalliopi; Poulia, Anthoula; Løvvik, Ole Martin; S. Azar, Amin; Mikheenko, Pavlo & Diplas, Spyridon [Show all 7 contributors for this article] (2021). Structural evolution of FeCoNi(AlMn)x high-entropy alloy and impact on magnetic properties: nano-scale STEM-EELS investigations.
• Almeida Carvalho, Patricia; Rahman, Jamil Ur; Soltani, Nayereh; Schrade, Matthias; Stange, Marit Synnøve Sæverud & Gunnæs, Anette Eleonora [Show all 8 contributors for this article] (2021). Functional high entropy antimonides and silicides.
• Almeida Carvalho, Patricia; Mayandi, Jeyanthinath; Rahman, Jamil Ur; Soltani, Nayereh; Schrade, Matthias & Gunnæs, Anette Eleonora [Show all 9 contributors for this article] (2021). Exploring the structure of high entropy oxides, silicides and antimonides for functional applications.
• Larsen, Aleksander; Poulia, Anthoula; S. Azar, Amin; Bazioti, Kalliopi; Almeida Carvalho, Patricia & Gunnæs, Anette Eleonora [Show all 9 contributors for this article] (2021). Identifying Magnetic Phases in Additively Manufactured High-Entropy Alloy FeCoNiAlxMnx.
• Bazioti, Kalliopi; Poulia, Anthoula; Løvvik, Ole Martin; S. Azar, Amin; Mikheenko, Pavlo & Diplas, Spyridon [Show all 7 contributors for this article] (2021). Advanced Scanning Transmission Electron Microscopy investigations of FeCoNi(AlMn)x high-entropy alloy: nanoscale structure and impact on magnetic properties.
• Bazioti, Kalliopi; Poulia, Anthoula; Løvvik, Ole Martin; Almeida Carvalho, Patricia; S. Azar, Amin & Mikheenko, Pavlo [Show all 8 contributors for this article] (2021). STEM-EELS investigations and Lorentz microscopy unravelling the structural evolution of FeCoNi(AlMn)x high-entropy alloy and its impact on magnetic properties.
• Poulia, Anthoula; S. Azar, Amin; Svec, Peter; Bazioti, Kalliopi; Belle, Branson & Gunnæs, Anette Eleonora [Show all 8 contributors for this article] (2020). Nanoscale Magnetic Properties of Additively Manufactured FeCoNiAlxMnx High-Entropy Alloys. Show summary

  Magnetic properties of High-Entropy Alloys based on the Fe-Co-Ni-Al-Mn system are reported. High-Entropy Alloys are cutting-edge technological materials containing five or more elements in relatively high concentrations (5–35 at.%) within one or several solid-state solutions. These solutions are stabilized at the nanometer scale due to the high contribution of the mixing entropy to the Gibbs free energy, which can overcome the enthalpic contribution. Two magnetic alloys are found in FeCoNiAlxMnx (1.6 at.%  x  7.8 at.%) samples processed by laser metal deposition. The magnetic techniques used to screen the materials were magneto-optical imaging and magnetic force microscopy. The former allows characterizing magnetic properties within the mm-μm scale, while the latter is efficient down to the nanometer scale. Magnetic screening confirms the importance of the nanostructure in defining magnetic properties of the alloys, and the trends in the magnetic behavior as a function of the alloy composition are revealed. The experimental results suggest that it is possible to form unique alloys, which may outperform conventional magnetic materials used in a variety of applications such as transformers, screening shields and wind power generators.

• Løberg, Monika; Karlsen, Ole Bjørn; Løvvik, Ole Martin; Almeida Carvalho, Patricia & Gunnæs, Anette Eleonora (2019). Characterization of phase transformations within the Cu-Pd-Sn system - a possible shape memory alloy for energy conversion.
• Løberg, Monika; Pike, Nicholas; Almeida Carvalho, Patricia; Karlsen, Ole Bjørn; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2019). Martensitic-like phase transformations within the Cu-Pd-Sn system .
• Løberg, Monika; Løvvik, Ole Martin; Almeida Carvalho, Patricia; Karlsen, Ole Bjørn & Gunnæs, Anette Eleonora (2019). Phase Transformations within the Cu-Pd-Sn system.
• Løberg, Monika; Pike, Nicholas; Karlsen, Ole Bjørn; Almeida Carvalho, Patricia; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2019). Characterization of phase transforming, Heusler based (Cu-Pd-Sn), alloys for energy harvesting. .
• Sunding, Martin Fleissner; Løberg, Monika; S. Azar, Amin; Stange, Marit Synnøve Sæverud; Almeida Carvalho, Patricia & Karlsen, Ole Bjørn [Show all 10 contributors for this article] (2019). The Need for a Multi-Technique Approach in the Search for New Phase-Transforming Materials. Show summary

  Introduction/Purpose Reversible diffusionless first-order phase transformations are a fundamental part of phase change materials and shape memory alloys [1]. Some of these materials even possess useful physical characteristics that show abrupt changes e.g. in their electrical[2] and magnetic [3] polarizations. These phase transformations can be studied using multiple techniques, enabling access to different types of information including length scales and time periods, but how should this characterisation be approached? Methods TEM studies give highly relevant data in this field of research, from detailed crystallographic structures, to relative orientations between grains and phases and to the phase transformation temperature. However, TEM analyses are time consuming and requires small sample sizes and ad hoc preparation. High-throughput measurement techniques are thus required in the search for improved compositions and new materials in order to rapidly assess the properties of many samples or samples with graded composition [4]. Optical methods (for example unpolarised and polarised microscopy and thermal imaging) and electric conductivity measurements can for example be used to map phase transformation temperatures much faster and on much larger areas than traditional TEM techniques. XRD and SEM-EDS-EBSD can then be applied to obtain initial crystallographic and microstructure information on an intermediate size scale, before TEM is applied for the in-depth study of the most relevant compositions. Results We applied this multi-pronged approach in the search for Heusler and half-Heusler alloys with a low temperature martensitic phase transformation and with low thermal hysteresis, with potential applications in waste heat energy harvesting. Conclusions Drawing advantage of the strengths of multiple analysis techniques – with respect to the obtainable information, the sample size and/or the time frame of the analyses – renders the search for new phase change materials more effective. It enables faster identification of potential target compositions and of sample areas optimal for in depth studies. Selected references [1] David Dye, Nature Materials14 (8), 760 (2015). [2] M. M. Vopson, Critical Reviews in Solid State and Materials Sciences40 (4), 223 (2015). [3] L. Huang, D. Y. Cong, L. Ma, Z. H. Nie, Z. L. Wang, H. L. Suo, Y. Ren, and Y. D. Wang, Applied Physics Letters108 (3) (2016). [4] M. L. Green, C. L. Choi, J. R. Hattrick-Simpers, A. M. Joshi, I. Takeuchi, S. C. Barron, E. Campo, T. Chiang, S. Empedocles, J. M. Gregoire, A. G. Kusne, J. Martin, A. Mehta, K. Persson, Z. Trautt, J. Van Duren, and A. Zakutayev, Applied Physics Reviews 4 (1), 011105 (2017).

• Strandbakke, Ragnar; Bjørheim, Tor Svendsen; Sørby, Magnus Helgerud; Wachowski, Sebastian Lech; Mielewczyk-Gryn, Aleksandra & Balaguer, Maria [Show all 9 contributors for this article] (2019). Hydration and hydrogenation of mixed conducting BaGd1‑xLaxCo2O6‑δ (BGLC).
• Kalyva, Maria Evangelou; Redekop, Evgeniy; Johansson, Niclas; Urpelainen, Samuli; Gunnæs, Anette Eleonora & Diplas, Spyridon [Show all 7 contributors for this article] (2019). AP-XPS study of bimetallic PtCu nanoparticles supported on SiO2 films.
• de Ruiter, Lisa; Austrheim, Håkon Olaf; Dysthe, Dag Kristian & Gunnæs, Anette Eleonora (2018). Quartz weathering associated with magnesium silicate hydrate cement precipitation.
• de Ruiter, Lisa; Austrheim, Håkon Olaf; Gunnæs, Anette Eleonora & Dysthe, Dag Kristian (2018). Quartz dissolution and M-S-H cement precipitation in a high pH ultramafic system.
• Løberg, Monika; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2018). Energy Conversion using Phase Transforming Materials - the Cu-Pd-Sn system.
• Løberg, Monika; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2018). Martensitic like phase transformations in the Cu-Pd-Sn system.
• Strandbakke, Ragnar; Gunnæs, Anette Eleonora; Carvalho, Patricia A.; Mielewczyk-Gryn, Aleksandra; Wachowski, Sebastian & Balaguer, Maria [Show all 8 contributors for this article] (2018). Coupled hydration, cation reorganization and red-ox in MIEC perovskites .
• Gunnæs, Anette Eleonora (2017). Evaluation of a thermoelectric p-n junction at the macro and nano scale by X-ray and electron probe techniques.
• Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Gunnæs, Anette Eleonora & Ulyashin, Alexander (2017). On the evolution of properties of ITO layers deposited on crystalline and amorphous Si upon heat treatments.
• Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Ramasse, Quentin; Gunnæs, Anette Eleonora & Ulyashin, Alexander (2017). A high resolution electron microscopy and spectroscopy study of interfaces in Si-based solar cell heterojunctions.
• Gunnæs, Anette Eleonora; Diplas, Spyros & Ulyashin, Alexander G. (2017). A TEM and XPS study of epitaxially grown amorphous hydrogenated silicon in solar cell structures.
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Berland, Kristian; Gunnæs, Anette Eleonora & Persson, Clas [Show all 8 contributors for this article] (2017). Structural Investigation of Ti1-xHfxNiySn Half-Heusler Compounds.
• Berland, Kristian; Eliassen, Simen Nut Hansen; Schrade, Matthias; Tofan, Raluca; Guzik, Matylda Natalia & Gunnæs, Anette Eleonora [Show all 11 contributors for this article] (2017). Using theory to understand thermoelectric materials.
• Gunnæs, Anette Eleonora (2016). Nanoscience with TEM at the Center for Material Science and Nanotechnology/NORTEM, Oslo, Norway.
• Granerød, Cecilie Skjold; Nguyen, Phuong Dan; Gunnæs, Anette Eleonora & Prytz, Øystein (2016). The Structure Physics group.
• Lervik, Adrian; Bjørheim, Tor Svendsen; Nguyen, Phuong Dan; Diplas, Spyridon; Haugsrud, Reidar & Gunnæs, Anette Eleonora (2016). Chemical and Structural Investigations of Grain Boundaries in Y-Doped BaZrO3.
• Schrade, Matthias; Echevarria-Bonet, Cristina; Eliassen, Simen Nut Hansen; Berland, Kristian; Persson, Clas & Tofan, Raluca [Show all 9 contributors for this article] (2016). Thermal Properties of XNiSn(X = Hf, Zr, Ti) half Heusler Alloys.
• Schrade, Matthias; Echevarria-Bonet, Cristina; Guzik, Matylda Natalia; Tofan, Raluca; Gunnæs, Anette Eleonora & Eliassen, Simen Nut Hansen [Show all 10 contributors for this article] (2016). Thermal properties of XNiSN (X = Ti, Zr, Hf) half Heusler alloys.
• Tofan, Raluca; Echevarria-Bonet, Cristina; Berland, Kristian; Schrade, Matthias; Sørby, Magnus Helgerud & Hauback, Bjørn Christian [Show all 10 contributors for this article] (2016). The effect of spark plasma sintering on structure and phase stability in half-Heusler thermoelectric alloys.
• Tofan, Raluca; Echevarria-Bonet, Cristina; Berland, Kristian; Schrade, Matthias; Sørby, Magnus Helgerud & Hauback, Bjørn Christian [Show all 10 contributors for this article] (2016). Microstructural characterization of spark plasma sintered (X,X’)NiSn half‐Heusler alloys.
• Lervik, Adrian; Haugsrud, Reidar; Diplas, Spyridon & Gunnæs, Anette Eleonora (2015). A TEM approach to BZY.
• Gunnæs, Anette Eleonora (2015). Atomkikking med Norges supermikroskop.
• Ulvestad, Asbjørn; Mæhlen, Jan Petter; Andersen, Hanne Flåten; Gunnæs, Anette Eleonora; Prytz, Øystein & Kirkengen, Martin (2015). Characterization of PECVD-Grown a-SiC:H for use as Coating for Silicon Thin Film Anodes in Li-Ion Batteries.
• Song, Xin; Valset, Kjetil; Graff, Joachim Seland; Thøgersen, Annett; Gunnæs, Anette Eleonora & Carbalho, Partricia [Show all 9 contributors for this article] (2015). Nano Improves Thermoelectric Performance. Show summary

  The rule of thumb for improving the performance of thermoelectric materials is to reduce the thermal conduction, which attributes to electron transport and phonon transport. Phonons are characterized by different wavelength, Short wavelength phonons are scattered by impurity atoms in alloyed matels, Mid- and Long wavelength phonns are scattered by the iuinterfaces. Nanostructuring can engineer the phonon transport by introduce numerous grain boundaries, thus increasing phonon scattering, further improving thermal resistance. The aim of the present study is the nano-grains of the thermoelectric material ZnSb and the correlation with thermal transport measurements. We explored cryomilling (by ball-milling powders at Cryogenic temperature) as a technique to created nano—powders of ZnSb for pressing into pellets. The effect of cryomilling flowed by hot-pressing of undoped ZnSb was investigated.

• Echevarria-Bonet, Cristina; Tofan, Raluca; Schrade, Matthias; Gunnæs, Anette Eleonora; Persson, Clas & Sørby, Magnus Helgerud [Show all 7 contributors for this article] (2015). Enhancement of the thermoelectric properties in nanostructured half-Heusler alloys.
• Fjellvåg, Øystein Slagtern; Sjåstad, Anja Olafsen; Haugsrud, Reidar & Gunnæs, Anette Eleonora (2015). Investigation of Novel Hydride Oxides for Holistic Understanding of Functional Materials.
• Song, Xin; Valset, Kjetil; Graff, Joachim Seland; Thøgersen, Annett; Gunnæs, Anette Eleonora & Luxsacumar, Sivakanesar [Show all 7 contributors for this article] (2014). Nanostructuring by Cryomilling of Undoped ZnSb.
• Song, Xin; Persson, Clas; Norby, Truls; Flage-Larsen, Espen; Karlsen, Ole Bjørn & Hansen, Vidar [Show all 15 contributors for this article] (2014). Conversion of Heat and Energy: Thermoelectrics.
• Løvvik, Ole Martin; Song, Xin; Valset, Kjetil; Flage-Larsen, Espen; Fjeld, Harald & Graff, Joachim Seland [Show all 14 contributors for this article] (2014). Thermoelectric materials from first principles to final applications: Basic and applied thermoelectrics in Oslo.
• Roaldset, Elen; Bering, Dag; Aerts, Maarten & Gunnæs, Anette E. (2013). Kaolinite Group minerals from weathered anorthosite, SW Norway. Berichte derDeutschen Ton- und Tonmineralgruppe e.V.. ISSN 1432-7007. 15, p. 27–27.
• Qureishy, Thomas; Hansen, Vidar; Karlsen, Ole Bjørn; Gunnæs, Anette Eleonora & Taftø, Johan (2012). Superstructures in Mg2Si1-xSnx.
• Larsen, Aleksander Amble & Gunnæs, Anette Eleonora (2021). A Correlated Study of FeNiCoMnxAlx - Magnetic, structural, and compositional properties of additive manufactured high-entropy alloy. Universitetet i Oslo.
• Røsvik, Mari Mathillas; Gunnæs, Anette Eleonora; Almeida Carvalho, Patricia & Schrade, Matthias (2021). Structural Characterization of High Entropy Metal Silicide Alloys An investigation of the Si:Cr:Fe:Co:Ni:Cu system. Universitetet i Oslo.
• Solemsli, Bjørn Gading; Olsbye, Unni; Gunnæs, Anette Eleonora & Gutterød, Emil Sebastian (2020). A Study of Catalytic Pt Nanoparticles inside a Nano-porous Functionalized UiO MOF-matrix for CO2-Hydrogenation . Universitetet i Oslo. Show summary

  Hydrogenation of carbon dioxide hasreceivedincreasingattentionin catalytic research the last decade as a sustainable alternativeforproducing high value chemicals thattodayare produced fromfossil fuels. The aim of this thesis has been two-fold: First, to study Pt nanoparticles formed in various UiO-66 and -67 metal-organic frameworks (MOFs) by Transmission Electron Microscopy (TEM), and second, to study the Pt-containing MOFs as catalysts for the CO2hydrogenation reaction.Three Zr-based UiO-66 MOF and nineUiO-67 MOF samples containing different amountsof functionalized linkers were impregnated withdifferent amounts ofK2PtCl4and reduced in H2at 350 ̊C for 4 hours to form Pt nanoparticles embedded in the MOF matrix.The samples were then testedin a H2/CO2feed at 8 bar and 170 ̊Cfor the hydrogenation reaction. After testing,TEMwas used to investigate the formation of Pt nanoparticles andtheir relationship with the surrounding MOF structure. The study revealed that, despite variable the linkers in the MOF,the conversion of CO2isdominated bythe reverse water-gas shift reaction,suggestingthat the linkers donot partakethe reactions mechanisms. Analysis usingTEMrevealedthat the Pt nanoparticles grow independently of its surroundings inside the MOFs with no observable growth relationshipwith the MOF. The nanoparticles are seen to grow into octahedral crystals that are larger than the pores in the framework. Samples with different amountsof missing linker type defects show that the presence of open Zr-node sitesenhances the selectivity towards methanol. A sample of Pt-functionalized UiO-67 with 10% [2,2’-bipyridine]5,5’-dicaboxylicacidlinker was oxidised toinduce missing linkerdefects post synthetically. After reduction in H2at 350 ̊C for 4 hours, the sample was oxidized in situin synthetic air for three different time spans. Careful analysis with N2-adsroption and TEM revealedthat the structure of the MOF deteriorates and loses accessible surface area with increasing timeon steam, while keeping the dispersion of the Pt nanoparticles. PXRD analysis revealedthe formation of tetragonal ZrO2. Extensive testsfrom 1-30 bar and 170-375 ̊C reveal a lower conversion and higher selectivity towards methanol for a fully calcined sample, indicating that the Zr-nodes behave similarlyto non-MOF ZrO2supports. Transient kinetic studies of the parent UiO-67 sample revealedthat the sample behaves similarlytopreviously studied systemsby Gutterød et al., and showed the presence of an inverse kinetic isotope effect for methane and methanolformation upon H2/D2exchange.

• Fjellvåg, Øystein; Sjåstad, Anja Olafsen & Gunnæs, Anette Eleonora (2019). Oxyhydrides - Synthesis, Crystal Structure and Properties. Universitetet i Oslo. ISSN 1501-7710. 2019(2153).
• Løberg, Monika & Gunnæs, Anette Eleonora (2017). Influence of Mn Stoichiometry on the Structure and Thermoelectric Properties of CaMn(1+y)O(3-d). Universitetet i Oslo. Show summary

  The energy consumption of present day society is ever increasing and the sources for more and cleaner energy is sought for. A possible contributor are thermoelectric generators, which convert parts of a heat flux directly into electrical energy. Unfortunately, the efficiency of current generators is too low for large scale commercialization, and new and better materials must be designed. In the present master project, the performance of n-type thermoelectric oxide CaMn(1+y)O(3-d) is attempted improved by creating precipitates within the nano-range. The precipitates could be anticipated to enhance phonon scattering, thereby lowering thermal conductivity and enhance the overall thermoelectric properties of the material. A sample series of CaMn(1+y)O(3-d), with composition y = 0, 0.020 , 0.036, 0.074 and 0.10, has been synthesized by solid state reaction and the microstructure and thermoelectric properties were characterized. Secondary phase, CaMn2O4, precipitates were found from X-ray diffraction and Scanning Electron Microscopy in the size range 5-10 um. Further investigations into the presence of nanoprecipitates were performed by Transmission Electron Microscopy finding no areas enriched in manganese within the CaMnO3 matrix. Electrical resistivity and Seebeck coefficient were measured from room temperature up to 600C finding a resistivity ranging from 20 - 100 mOhm cm and Seebeck coefficient from -300 to -200 uVK-1, showing no trend with manganese content. Thermal conductivity measurements were performed, showing a thermal conductivity between 2.3 - 3.6 Wm-1K-1, however no trend with varying manganese content was observed. Further, the obtained thermoelectric data was compared with samples fabricated using a different synthesis method, yielding similar results and no significant variations was observed. The absence of a Mn-dependency in all transport parameters was carefully confirmed by a thorough investigation of potential experimental influences, like sample porosity, impurity level and measurement uncertainty. Finally, the results are qualitatively rationalized using a simple Callaway model for the thermal conductivity. The concluding remarks are that all manganese excess will manifest as secondary phase CaMn2O4 and no manganese rich precipitates will exist within the CaMnO3 matrix. The variation in manganese content does not influence the thermoelectric properties of CaMn(1+y)O(3-d).

• Lervik, Adrian; Haugsrud, Reidar; Diplas, Spyridon & Gunnæs, Anette Eleonora (2016). Structural- and Compositional Investigations of Grain Boundaries in Y-Doped BaZrO3. Universitetet i Oslo.
• Povia, Mauro; Sartori, Sabrina & Gunnæs, Anette Eleonora (2015). In Situ Operando SAXS and WAXS Characterization of the Anode Materials (a-P/C and FeSb2) for Rechargeable Sodium Ion Batteries. 7Letras.

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