Matthias Schrade

• Jensen, Ingvild Julie Thue; Ali, Ayaz; Zeller, Patrick; Amati, Matteo; Schrade, Matthias; Vullum, Per Erik; Benthem Muñiz, Marta; Bisht, Prashant; Taniguchi, Takashi; Watanabe, Kenji; Mehta, Bodh R.; Gregoratti, Luca & Belle, Branson (2021). Direct Observation of Charge Transfer between NOx and Monolayer MoS2 by Operando Scanning Photoelectron Microscopy. ACS Applied Nano Materials.  ISSN 2574-0970. . doi: 10.1021/acsanm.1c00137
• Gunnæs, Anette Eleonora; Tofan, Raluca; Berland, Kristian; Gorantla, Sandeep Madhukar; Storaas, Thomas Aarflot; Desissa, Temesgen Debelo; Schrade, Matthias; Persson, Clas; Einarsrud, Mari-Ann; Wiik, Kjell; Norby, Truls Eivind & Kanas, Nikola (2020). Chemical stability of Ca3Co4−xO9+δ/CaMnO3−δ p–n junction for oxide-based thermoelectric generators. RSC Advances.  ISSN 2046-2069.  10(9), s 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.

• Schrade, Matthias; Berland, Kristian; Kosinskiy, Andrey; Heremans, Joseph P. & Finstad, Terje (2020). Shallow Impurity Band in ZrNiSn. Journal of Applied Physics.  ISSN 0021-8979.  127(4) . doi: 10.1063/1.5112820 Full text in Research Archive. Show summary

  ABSTRACT ZrNiSn and related half Heusler compounds are candidate materials for efficient thermoelectric energy conversion with a reported thermoelectric figure-of-merit of n-type ZrNiSn exceeding unity. Progress on p-type materials has been more limited, which has been attributed to the presence of an impurity band, possibly related to Ni interstitials in a nominally vacant 4d position. The specific energetic position of this band, however, has not been resolved. Here, we report the results of a concerted theory-experiment investigation for a nominally undoped ZrNiSn, based on the electrical resistivity, the Hall coefficient, the Seebeck coefficient, and the Nernst coefficient, measured in a temperature range from 80 to 420 K. The results are analyzed with a semianalytical model combining a density functional theory (DFT) description for ideal ZrNiSn, with a simple analytical correction for the impurity band. The model provides a good quantitative agreement with experiment, describing all salient features in the full temperature span for the Hall, conductivity, and Seebeck measurements, while also reproducing key trends in the Nernst results. This comparison pinpoints the impurity band edge to 40 meV below the conduction band edge, which agrees well with a separate DFT study of a supercell containing Ni interstitials. Moreover, we corroborate our result with a separate study of the ZrNiSn0.9Pb0.1 sample showing similar agreement with an impurity band edge shifted to 32 meV below the conduction band.

• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Almeida Carvalho, Patricia; Berland, Kristian; Sørby, Magnus Helgerud; Persson, Clas; Gunnæs, Anette Eleonora & Hauback, Bjørn (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, s 3330- 3342 . doi: 10.1039/c9ce00046a Full text in Research Archive.
• Bittner, Michael; Kanas, Nikola; Hinterding, Richard; Steinbach, Frank; Räthel, Jan; Schrade, Matthias; Wiik, Kjell; Einarsrud, Mari-Ann & Feldhoff, Armin (2019). A comprehensive study on improved power materials for high-temperature thermoelectric generators. Journal of Power Sources.  ISSN 0378-7753.  410-411, s 143- 151 . doi: 10.1016/j.jpowsour.2018.10.076 Full text in Research Archive. Show summary

  Dense Ca3Co4O9-NaxCoO2-Bi2Ca2Co2O9 (CCO-NCO-BCCO) nanocomposites were produced from sol-gel derived Ca2.25Na0.3Bi0.35Tb0.1Co4O9 powder by four methods: Hot-pressing (HP), spark plasma sintering (SPS) and pressureless sintering in air or O2 atmosphere. Nanocomposites from HP and SPS revealed nanosized grains and showed a thermoelectric power factor of 4.8 and 6.6 μW cm−1 K−2, respectively, at 1073 K in air. A dense 2D nanocomposite with structures on multiple length scales and enhanced thermoelectric properties was obtained from pressureless sintering in O2 atmosphere. The resulting 2D nanocomposite enabled the simultaneous increase in isothermal electrical conductivity σ and Seebeck coefficient α, and showed a thermoelectric power factor of 8.2 μW cm−1 K−2 at 1073 K in air. The impact of materials with enhanced electrical conductivity and power factor on the electrical power output of thermoelectric generators was verified in prototypes. A high electrical power output and power density of 22.7mW and 113.5mW cm−2, respectively, were obtained, when a hot-side temperature of 1073 K and a temperature difference of 251 K were applied. Different p- and n-type materials were used to verify the effect of the thermoelectric figure-of-merit zT and power factor on the performance of thermoelectric generators.

• Schrade, Matthias & Finstad, Terje (2018). Using the Callaway Model to Deduce Relevant Phonon Scattering Processes: The Importance of Phonon Dispersion. Physica status solidi (b).  ISSN 0370-1972.  255(12), s 1- 6 . doi: 10.1002/pssb.201800208
• Desissa, Temesgen D.; Schrade, Matthias & Norby, Truls Eivind (2018). Electrical Properties of a p–n Heterojunction of Li-Doped NiO and Al-Doped ZnO for Thermoelectrics. Journal of Electronic Materials.  ISSN 0361-5235.  47(9), s 5296- 5301 . doi: 10.1007/s11664-018-6394-3 Show summary

  The electrical properties of a p–n heterojunction of polycrystalline p-type Ni0.98Li0.02O and n-type Zn0.98Al0.02O have been investigated for potential applications in high-temperature oxide-based thermoelectric generators without metallic interconnects. Current–voltage characteristics of the junction were measured in a two-electrode setup in ambient air at 500–1000°C. The resistance and rectification of the junction decreased with increasing temperature. A non-ideal Shockley diode model was used to fit the measured current–voltage data in order to extract characteristic parameters of the junction, such as area specific series resistance Rs and parallel shunt resistance Rp, non-ideality factor, and the saturation current density. Rs and Rp decreased exponentially with temperature, with activation energies of 0.4 ± 0.1 eV and 1.1 ± 0.2 eV, respectively. The interface resistance of the direct p–n junction studied here is as such too high for practical applications in thermoelectrics. However, it is demonstrated that it can be reduced by an order of magnitude by using a composite of the individual materials at the interface, yielding a large effective contact area.

• Schrade, Matthias; Maso Carcases, Nahum; Perejón, Antonio; Pérez-Maqueda, Luis A. & West, Anthony R. (2017). Defect chemistry and electrical properties of BiFeO3. Journal of Materials Chemistry C.  ISSN 2050-7526.  5(38), s 10077- 10086 . doi: 10.1039/c7tc03345a
• Cerretti, G; Schrade, Matthias; Song, Xin; Balke, B; Lu, H; Weidner, T; Lieberwirth, I; Panthofer, M; Norby, Truls Eivind & Tremel, Wolfgang (2017). Thermal stability and enhanced thermoelectric properties of the tetragonal tungsten bronzes Nb8-xW9+xO47 (0 < x < 5). Journal of Materials Chemistry A.  ISSN 2050-7488.  5(20), s 9768- 9774 . doi: 10.1039/c7ta01121k
• Schrade, Matthias; Berland, Kristian; Eliassen, Simen Nut Hansen; Guzik, Matylda Natalia; Echevarria-Bonet, Cristina; Sørby, Magnus Helgerud; Jenus, Petra; Hauback, Bjørn; Tofan, Raluca; Gunnæs, Anette Eleonora; Persson, Clas; Løvvik, Ole Martin & Finstad, Terje (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.
• Song, Xin; Schrade, Matthias; Maso Carcases, Nahum & Finstad, Terje (2017). Zn vacancy formation, Zn evaporation and decomposition of ZnSb at elevated temperatures: Influence on the microstructure and the electrical properties. Journal of Alloys and Compounds.  ISSN 0925-8388.  710, s 762- 770 . doi: 10.1016/j.jallcom.2017.03.339 Full text in Research Archive. Show summary

  The influence of annealing on the microstructure and electrical properties of undoped polycrystalline ZnSb samples has been investigated by different experimental techniques. In situ XRD in an argon at- mosphere showed that ZnSb powders decompose at 300 C, which is attributed to Zn evaporation. In situ SEM in a moist atmosphere showed fast surface deterioration at 450 C and above, reflecting decom- position of ZnSb and the formation of metallic Sb precipitates. The rate of Zn loss in a reducing atmo- sphere was determined by thermogravimetry and related to the Zn partial vapor pressure. The increase of the hole carrier concentration of ZnSb measured at room temperature after heat treatment was correlated with Zn evaporation at elevated temperature. The carrier concentration after annealing at 400 C is consistent with an activation energy for Zn vacancy formation of 0.4 eV and a maximum Zn deficiency x of Zn1-xSb of 1 10 3.

• Vøllestad, Einar; Schrade, Matthias; Segalini, Julie; Strandbakke, Ragnar & Norby, Truls Eivind (2017). Relating defect chemistry and electronic transport in the double perovskite Ba1-xGd0.8La0.2+xCo2O6-d (BGLC). Journal of Materials Chemistry A.  ISSN 2050-7488.  5(30), s 15743- 15751 . doi: 10.1039/c7ta02659e Full text in Research Archive.
• Schrade, Matthias; Magraso, Anna; Galeckas, Augustinas; Finstad, Terje & Norby, Truls (2016). The Band Gap of BaPrO3 Studied by Optical and Electrical Methods. Journal of The American Ceramic Society.  ISSN 0002-7820.  99(2), s 492- 498 . doi: 10.1111/jace.13961
• Heinrich, Christophe P.; Schrade, Matthias; Cerretti, Giacomo; Lieberwirth, Ingo; Leidich, Patrick; Schmitz, Andreas; Fjeld, Harald; Müller, Eckhard; Finstad, Terje; Norby, Truls & Tremel, Wolfgang (2015). Tetragonal tungsten bronzes Nb8-xW9+xO47-d: optimization strategies and transport properties of a new n-type thermoelectric oxide. Materials Horizons.  ISSN 2051-6347.  2(5), s 519- 427 . doi: 10.1039/c5mh00033e
• Schrade, Matthias; Norby, Truls & Finstad, Terje (2015). Hall effect measurements on thermoelectric Ca3Co4O9: On how to determine the charge carrier concentration in strongly correlated misfit cobaltites. Journal of Applied Physics.  ISSN 0021-8979.  117(20) . doi: 10.1063/1.4921861 Full text in Research Archive.
• Sagarna, Leyre; Populoh, Sascha; Shkabko, Andrey; Eilertsen, James; Maegli, Alexandra E.; Hauert, Roland; Schrade, Matthias; Karvonen, Lassi & Weidenkaff, Anke (2014). Influence of the Oxygen Content on the Electronic Transport Properties of SrxEu1–xTiO3-δ. Journal of Physical Chemistry C.  ISSN 1932-7447.  118(15), s 7821- 7831 . doi: 10.1021/jp500480c
• Schrade, Matthias; Casolo, Simone; Graham, Paul J.; Ulrich, Clemens; Li, Sean; Løvvik, Ole Martin; Finstad, Terje & Norby, Truls (2014). Oxygen nonstoichiometry in (Ca2CoO3)0.62(CoO2): a combined experimental and computational study. Journal of Physical Chemistry C.  ISSN 1932-7447.  118(33), s 18899- 18907 . doi: 10.1021/jp5048437 Show summary

  The oxygen nonstoichiometry in the misfit calcium cobaltite (Ca2CoO3)0.62(CoO2) has been studied experimentally and by density functional theory (DFT) calculations. The standard oxidation enthalpy ΔH0Ox of oxygen deficient (Ca2CoO3)0.62(CoO2) was measured directly using simultaneous thermogravimetry and differential scanning calorimetry. ΔH0Ox was found to be in agreement with the prediction from a previously published defect chemical model based on purely thermogravimetrical analysis. A series of samples with different oxygen vacancy concentration was prepared by annealing in air, followed by rapid quenching. Room-temperature Raman spectroscopy showed a sharp mode at 700 cm–1 decreasing in intensity with increasing vacancy concentration. We discuss this observation as evidence for oxygen vacancies being preferably formed within the central layer of the Ca2CoO3 subsystem. DFT calculations demonstrated that the calculated electronic structure is sensitive to the chosen model of the crystal structure. Still, for all investigated models, the standard formation enthalpy of oxygen vacancies within the Ca2CoO3 moiety was much lower than that for a site within the CoO2 layer, in agreement with the presented experimental data.

• Schrade, Matthias; Fjeld, Harald; Finstad, Terje & Norby, Truls (2014). Electronic Transport Properties of [Ca2CoO3-δ]q[CoO2]. Journal of Physical Chemistry C.  ISSN 1932-7447.  118(6), s 2908- 2918 . doi: 10.1021/jp409581n
• Schrade, Matthias; Fjeld, Harald; Norby, Truls & Finstad, Terje (2014). Versatile apparatus for thermoelectric characterization of oxides at high temperatures. Review of Scientific Instruments.  ISSN 0034-6748.  85(10) . doi: 10.1063/1.4897489
• Schrade, Matthias; Kabir, Rezaul; Li, Sean; Norby, Truls & Finstad, Terje (2014). High temperature transport properties of thermoelectric CaMnO3-d - Indication of strongly interacting small polarons. Journal of Applied Physics.  ISSN 0021-8979.  115 . doi: 10.1063/1.4868321 Full text in Research Archive.

View all works in Cristin

• Jeyanthinath, Mayandi; Stange, Marit Synnøve Sæverud; Dahl, Øystein; Sunding, Martin Fleissner; Sagvolden, Espen; Flage-Larsen, Espen; Schrade, Matthias; Deuermeier, J.; Fortunato, Elvira; Diplas, Spyridon; Løvvik, Ole Martin; Finstad, Terje & Almeida Carvalho, Patricia (2020). Functional Properties of CrFeCoNiCu and GeFeCoNiCu oxides. Show summary

  The present work explores the concept of high-entropy alloys to design FeCoNi-based oxides suitable for functional applications. Fundamental changes in electronic behavior produced by metal substitution and variable oxygen content were screened to investigate the potential of these materials for specific applications, such as transparent conductors and thermoelectric materials. Elements with atomic radius similar to the average value expected for FeCoNi have been selected for substitutional replacement: (i) Cr and Cu as relatively abundant commodities with intensive industrial application and (ii) Ge due its semiconductor nature. CrFeCoNiCu and GeFeCoNiCu thin films with variable oxygen concentration were deposited by reactive DC magnetron sputtering onto optically transparent substrates and characterized by structural, spectroscopic and electrical methods. Transmission electron microscopy showed that for low oxygen content the materials adopted an fcc-type structure while the NaCl-structure was found for higher oxygen concentrations. X-ray-photoelectron spectroscopy was used to characterize the oxidation state of the metals. The resistivity measured at room temperature ranged from 10-4 to values above 104 Ω.cm. Hall measurements and Seebeck measurements show that both electrons and holes contribute to conduction and that at room temperature the Hall coefficient and Seebeck coefficient have different sign. This behaviour is discussed in terms of the structural analysis and suggested electronic model of the films.

• Løvvik, Ole Martin; Graff, Joachim Seland; Schrade, Matthias; Sunding, Martin Fleissner; Wright, Daniel Nilsen; Song, Xin; Finstad, Terje; Enebakk, Erik; Tollefsen, Torleif Andre & Skomedal, Gunstein (2020). Silicide module produced in the TESil project.
• Løvvik, Ole Martin; Berland, Kristian; Remonato, Filippo; Sagvolden, Espen; Flage-Larsen, Espen; Schrade, Matthias; Tanusilp, S.; Kurosaki, K.; Tabib, Mandar; Persson, Clas; Shulumba, Nina; Hellman, Olle & Skomedal, Gunstein (2019). Screening thermoelectric materials with ab initio atomistic modelling and machine learning techniques.
• Mayandi, Jeyanthinath; Stange, Marit Synnøve Sæverud; Sagvolden, Espen; Sunding, Martin Fleissner; Dahl, Øystein; Schrade, Matthias; Deuermeier, J.; Fortunato, E.; Løvvik, Ole Martin; Diplas, Spyridon; Finstad, Terje & Calvaho, Patricia (2019). Development of sputtered HEA thin films and their functional properties.
• Mayandi, Jeyanthinath; Stange, Marit Synnøve Sæverud; Dahl, Øystein; Sunding, Martin Fleissner; Sagvolden, Espen; Schrade, Matthias; Deuermeier, J.; Fortunato, Elvira; Diplas, Spyridon; Løvvik, Ole Martin; Finstad, Terje & Almeida Carvalho, Patricia (2019). Exploring functional properties of high entropy oxides. Show summary

  The present work explores the concept of high-entropy alloys to design FeCoNi-based oxides suitable for functional applications. Fundamental changes in electronic behaviour produced by metal substitution and variable oxygen content were screened to investigate the potential of these materials for specific applications, such as transparent conductors and thermoelectric materials. Elements with atomic radius similar to the average value expected for FeCoNi have been selected for substitutional replacement: (i) Cr and Cu as relatively abundant commodities with intensive industrial application and (ii) Ge due its semiconductor nature. We have sputtered CrFeCoNiCu and of GeFeCoNiCu thin films onto insulating and optically transparent substrates in order to measure electrical and optical properties. The deposition was done by reactive DC magnetron sputtering from targets with equimolar proportions of the metallic elements using atmospheres ranging from 0 to 20 at.% O2 /Ar. The films where characterized by structural, spectroscopic and electrical methods. Transmission electron microscopy showed that for oxygen content up to 8 at.% the materials adopted an fcc-type structure while the NaCl-structure was found for higher oxygen concentrations. X-ray-photoelectron spectroscopy was used to characterize the oxidation state of the metals. Standard absorption analysis by UV-VIS spectrometry revealed that the films had bandgaps ranging from 0.8 to 2.8 eV. The resistivity measured at RT ranged from 10-4 to values above 104 Ω.cm. Hall measurements and Seebeck measurements indicated that both electrons and holes contribute to conduction and at RT the Hall coefficient and Seebeck coefficients have different sign. This behaviour is discussed in terms of the structural analysis and suggested electronic model of the films. In conclusion, the optical band gap and resistivity of the materials produced span over large ranges demonstrating potential for a variety of functional applications.

• Mayandi, Jeyanthinath; Stange, Marit Synnøve Sæverud; Sagvolden, Espen; Sunding, Martin Fleissner; Dahl, Øystein; Schrade, Matthias; Deuermeier, J.; Fortunato, E.; Løvvik, Ole Martin; Diplas, Spyridon; Almeida Carvalho, Patricia & Terje G, Finstad (2019). Structural and Electrical Properties of Sputtered HEA Thin Films of CrFeCoNiCu and their Oxidation Studies. Show summary

  High-entropy alloys (HEAs) represent a class of materials that is intensively investigated for a range of possible applications. They generally show a high degree of phase stability by the high entropy while the structure is a random atom position disorder unlike other alloys which can influence physical properties differently than regular alloys. In general, there are few studies on oxidation of HEA and studies on adding oxygen during the fabrication of HEA. In this study we have sputtered thin films of CrFeCoNiCu onto insulating and optically transparent substrates in order to measure structural, electrical and optical functional properties. We have varied the oxygen pressure in the sputtering environment as well as oxidizing the samples at elevated temperatures after deposition. Optical and electrical characterization was performed on films sputter deposited on fused quartz wafers. The films were characterized by TEM, XRD and XPS. The films with no intentional oxygen had an FCC structure with a texture showing strong (111) preferred orientation as seen by XRD. TEM analysis showed columnar morphology with twins parallel to (111) planes. Samples sputtered under high oxygen content showed a simple NaCl structure(FeO). The samples were annealed in air and O2 ambient in the temperature range of 300 to 500 °C. This caused an oxide layer growing on top of the FCC structure. XPS was utilized to find the atomic compositions and chemical stated of the elements. Hall measurements and Seebeck measurements were performed on the as prepared and oxidized films from 10 K to 600K. For the FCC structure the resistivity was a factor 104 higher than the elemental metals while can be satisfactory described by electron phonon scattering by the Bloch-Grüneisen description and the low temperature negative temperature effect by the Kondo effect. The sign of the Hall coefficient was positive while the Seebeck coefficient was negative, indicating the Fermi surface containing pockets of electrons and holes and an energy dependent scattering time. A detailed comparison of the as prepared and the oxidized thin films will be discussed in terms of the structural chemical and electrical properties of the grown films. In addition the electric properties will be discussed in terms of a model considering electronic structure and scattering.

• Mayandi, Jeyanthinath; Stange, Marit Synnøve Sæverud; Sunding, Martin Fleissner; Schrade, Matthias; Deuermeier, J.; Fortunato, E.; Løvvik, Ole Martin; Diplas, Spyridon; Almeida Carvalho, Patricia & Terje G, Finstad (2019). Physical properties of sputtered CrFeCoNiCu thin films on quartz substrate. Show summary

  Equiatomic high entropy alloys (HEA) have attracted considerable interest due to their exceptional properties, which might be closely related to their extreme disorder induced by chemical complexity. We have sputtered thin films of CrFeCoNiCu onto insulating and optically transparent substrates in order to measure electrical and optical functional properties. After several optimizations desired sputtering conditions were obtained for the deposition of CrFeCoNiCu onto fused quartz wafers. All the samples were characterized by structural, chemical and electrical methods. The as prepared films had fcc-type structure. Hall measurements were performed from 10 K to 600K. The resistivity was a factor 104 higher than the elemental metals and the temperature dependence was different. The sign of the Hall coefficient indicates that the film was dominated by holes, while the Seebeck coefficient was negative and dominated by electrons. The electric properties will be discussed in terms of a model considering electronic structure and scattering.

• Berland, Kristian; Eliassen, Simen Nut Hansen; Løvvik, Ole Martin; Persson, Clas & Schrade, Matthias (2018). Computational Engineering of Thermoelectric Materials.
• Berland, Kristian; Eliassen, Simen Nut Hansen; Schrade, Matthias; Tofan, Raluca; Guzik, Matylda Natalia; Gunnæs, Anette Eleonora; Finstad, Terje; Katre, Anikta; Madsen, Georg; Persson, Clas & Løvvik, Ole Martin (2017). Using theory to understand thermoelectric materials.
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Berland, Kristian; Gunnæs, Anette Eleonora; Persson, Clas; Sørby, Magnus Helgerud & Hauback, Bjørn (2017). Structural Investigation of Ti1-xHfxNiySn Half-Heusler Compounds.
• Schrade, Matthias (2017). Nye materialer lager strøm av temperaturforskjeller. Apollon : Forskningsmagasin for Universitetet i Oslo.  ISSN 0803-6926.  27(1), s 26- 29
• Schrade, Matthias; Berland, Kristian; Guzik, Matylda Natalia; Løvvik, Ole Martin & Finstad, Terje (2017). Why does the thermal conductivity of XNiSn vary for nominally identical samples?.
• Løvvik, Ole Martin; Eliassen, Simen Nut Hans; Berland, Kristian; Song, Xin; Schrade, Matthias; Shulumba, N.; Hellman, O.; Katre, A & Madsen, G. (2016). Predicting the thermoelectric figure of merit from first principles.
• Riis, Henrik; Schrade, Matthias & Song, Xin (2016, 01. desember). Termoelektrisk strøm av varme overflater. [Fagblad].
• Schrade, Matthias (2016, 18. oktober). 900 deltok på festival. [TV].  NRK.
• Schrade, Matthias (2016, 01. desember). Å hente strøm fra varme overflater kan bli like vanlig som å hente strøm fra sollys. [Internett].  Teknisk Ukeblad.
• Schrade, Matthias; Echevarria-Bonet, Cristina; Eliassen, Simen Nut Hansen; Berland, Kristian; Persson, Clas; Tofan, Raluca; Løvvik, Ole Martin; Gunnæs, Anette Eleonora & Finstad, Terje (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; Berland, Kristian; Persson, Clas; Løvvik, Ole Martin & Finstad, Terje (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; Persson, Clas; Prytz, Øystein; Hansen, Vidar & Gunnæs, Anette Eleonora (2016). Microstructural characterization of spark plasma sintered (X,X’)NiSn half‐Heusler alloys.
• Tofan, Raluca; Echevarria-Bonet, Cristina; Berland, Kristian; Schrade, Matthias; Sørby, Magnus Helgerud; Hauback, Bjørn Christian; Persson, Clas; Prytz, Øystein; Hansen, Vidar & Gunnæs, Anette Eleonora (2016). The effect of spark plasma sintering on structure and phase stability in half-Heusler thermoelectric alloys.
• Desissa, Temesgen D.; Schrade, Matthias & Norby, Truls (2015). Interface properties of p-Ca3Co4O9 and n-Sr0.9 La0.1 TiO3 junction of oxide thermoelectric materials for oxide thermoelectric modules. Show summary

  Heat to electricity conversion is the technique that is used for waste heat recovery. Thermoelectric generators are potential candidates for this conversion of waste heat in to useful electrical power. Among different classes of thermoelectric materials, oxide thermoelectric materials are gaining much attention and emerging as a promising materials to be utilized for construction of oxide thermoelectric generators (OTEGs). The reason behind is that these materials are stable at high temperature, non-toxic and additionally these oxides are environmentally friendly. OTEGs can be constructed from n and p-type oxide thermoelectric materials and assembling them into a module. The two oxide legs can be brought to direct contact to each other to prevent the usage of metallic interconnects. This will reduce the cost associated to some of the precious metals in the metallic interconnect and some of these metals are toxic and volatile at high temperature. Additionally, these metallic interconnects contribute to the Ohmic loss at their contact between the two n and p-oxide legs. In present work, we are investigating the properties of inter-diffusion of species between the couples and the co-existence of these species at different atmosphere and temperature. Ca3Co4O9 and Sr0.9 La0.1 TiO3 powders were used as p-type and n-type oxide thermoelectric materials, respectively. The powders were mixed using ball milling for several hours in a proper stoichiometric amounts. Then, the powders were filtered and dried in oven. The dried powder was pressed in to a pellet form and subjected to sintering (heating at high temperature) for several hours. Then the sintered sample was characterized. The characterization techniques that could be employed are SEM/EDS, TEM/EDS, EPMA, and XRD analysis. Then, electrical and thermoelectric properties will be measured on the sample.

• Echevarria-Bonet, Cristina; Tofan, Raluca; Schrade, Matthias; Gunnæs, Anette Eleonora; Persson, Clas; Sørby, Magnus Helgerud & Hauback, Bjørn (2015). Enhancement of the thermoelectric properties in nanostructured half-Heusler alloys.
• Heinrich, Christophe P.; Schrade, Matthias; Cerretti, Giacomo; Malerød-Fjeld, Harald; Finstad, Terje; Norby, Truls & Tremel, Wolfgang (2015). Tetragonal Tungsten Bronzes Nb8−xW9+xO47−δ: Optimization Strategies and Transport Properties of a New Group of n-Type Thermoelectric Oxides.
• Sahoo, Prangya Parimita; Schrade, Matthias; Grandcolas, Mathieu; Polfus, Jonathan M.; Foss, Carl Erik Lie; Sunde, Svein & Norby, Truls (2015). Photoelectrocatalytic conversion of water, carbon dioxide, and nitrogen to fuels and chemicals.
• Løvvik, Ole Martin; Song, Xin; Valset, Kjetil; Flage-Larsen, Espen; Fjeld, Harald; Graff, Joachim Seland; Schrade, Matthias; Karlsen, Ole Bjørn; Larsson, Andreas; Casolo, Simone; Prytz, Øystein; Norby, Truls; Finstad, Terje; Gunnæs, Anette Eleonora & Taftø, Johan (2014). Thermoelectric materials from first principles to final applications: Basic and applied thermoelectrics in Oslo.
• Schrade, Matthias (2014). On the Oxygen Nonstoichiometry in Thermoelectric Oxides.
• Song, Xin; Persson, Clas; Norby, Truls; Flage-Larsen, Espen; Karlsen, Ole Bjørn; Hansen, Vidar; Gunnæs, Anette Eleonora; Prytz, Øystein; Løvvik, Ole Martin; Finstad, Terje; Valset, Kjetil; Cui, Xuemei; Taftø, Johan; Fjeld, Harald; Hauback, Bjørn & Schrade, Matthias (2014). Conversion of Heat and Energy: Thermoelectrics.
• Fjeld, Harald; Schrade, Matthias; Norby, Truls & Finstad, Terje (2013). Defects and transport in thermoelectric calcium cobalt oxide.
• Løvvik, Ole Martin; Casolo, Simone; Fjeld, Harald; Schrade, Matthias & Norby, Truls (2013). Fundamental properties of oxygen deficient calcium cobalt oxide.
• Norby, Truls; Fjeld, Harald; Schrade, Matthias; Finstad, Terje; Løvvik, Ole Martin & Casolo, Simone (2013). On synthesis, phase purity, and oxygen stoichiometry of sodium and calcium cobaltate thermoelectrics. Show summary

  Relatively high concentrations of oxygen vacancies and effects on thermoelectric properties have been reported in the literature on state-of-the-art thermoelectric sodium cobaltates. However, first principle calculations suggest high energies and low concentrations of such vacancies. Experiments in our laboratory indicate that apparent oxygen non-stoichiometry may have stemmed from secondary phases present after decomposition in two-phase regions during synthesis and measurements. In a similar manner, experimental evaluation and defect-chemical interpretation of non-stoichiometry in calcium cobaltate thermoelectrics are troubled by non-trivial synthesis and sample fabrication. Recent results on these matters are presented and discussed.

• Schrade, Matthias; Fjeld, Harald; Finstad, Terje & Norby, Truls (2013). High temperature electronic transport in (Ca2CoO3-x)q(CoO2).
• Schrade, Matthias; Kabir, Rezaul; Li, Sean; Norby, Truls & Finstad, Terje (2013). Effect of oxygen content on the thermoelectric properties of CaMnO3-x.
• Schrade, Matthias; Kabir, Rezaul; Li, Sean; Norby, Truls & Finstad, Terje (2013). High-temperature thermoelectric properties of CaMnO3-x.
• Fjeld, Harald; Schrade, Matthias & Norby, Truls (2012). The role of phase relations and Ca to Co ratio in thermoelectric properties of Ca3Co4O9+d.
• Schrade, Matthias; Fjeld, Harald & Norby, Truls (2012). Simultaneous measurement of Seebeck coefficient and conductivity at high temperatures and in controlled atmospheres.
• Schrade, Matthias; Fjeld, Harald; Norby, Truls & Finstad, Terje (2012). Influence of oxygen non-stoichiometry on thermoelectric properties of Ca3Co4O9+x.

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