Finn forfatter "Løvvik, Ole Martin"

Viser treff 1-20 av 23

  • Application of machine learning-based selective sampling to determine BaZrO3 grain boundary structures 
    Bondevik, Tarjei; Kuwabara, Akihide; Løvvik, Ole Martin (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)
    A selective sampling procedure is applied to reduce the number of density functional theory calculations needed to find energetically favorable grain boundary structures. The procedure is based on a machine learning algorithm ...
  • Attaining Low Lattice Thermal Conductivity in Half-Heusler Sublattice Solid Solutions: Which Substitution Site Is Most Effective? 
    Tranås, Rasmus André; Løvvik, Ole Martin; Berland, Kristian (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Low thermal conductivity is an important materials property for thermoelectricity. The lattice thermal conductivity (LTC) can be reduced by introducing sublattice disorder through partial isovalent substitution. Yet, ...
  • Boron-implanted 3C-SiC for intermediate band solar cells 
    Ma, Quanbao; Galeckas, Augustinas; Azarov, Alexander; Thøgersen, Annett; Carvalho, Patricia; Wright, Daniel Nilsen; Diplas, Spyridon; Løvvik, Ole Martin; Jokubavicius, Valdas; Liu, Xinyu; Sun, Jianwu; Syväjärvi, Mikael; Svensson, Bengt Gunnar (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)
    Sublimation-grown 3C-SiC crystals were implanted with 2 atomic percent of boron ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 8.5×1016 atoms/cm2. The samples were then ...
  • Calculation of the anisotropic coefficients of thermal expansion: A first-principles approach 
    Pike, Nicholas; Løvvik, Ole Martin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Predictions of the anisotropic coefficients of thermal expansion are needed to not only compare to experimental measurement, but also as input for macroscopic modeling of devices which operate over a large temperature ...
  • Controlling the Electrical Properties of Reactively Sputtered High Entropy Alloy CrFeNiCoCu Films 
    Mayandi, Jeyanthinath; Finstad, Terje Gunnar; Stange, Marit Synnøve Sæverud; Vasquez, Geraldo Cristian; Sunding, Martin Fleissner; Løvvik, Ole Martin; Diplas, Spyridon; Almeida Carvalho, Patricia (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Oxide-containing films were made by reactively sputtering a high-entropy alloy target of CrFeCoNiCu. We report on a wide range of changes to the electrical properties made by different heat treatments in oxidizing and ...
  • Cubic silicon carbide as a potential photovoltaic material 
    Syväjärvi, Mikael; Ma, Quanbao; Jokubavicius, Valdas; Galeckas, Augustinas; Sun, Jianwu; Liu, Xinyu; Jansson, Mattias; Wellmann, Peter; Linnarsson, Margareta; Runde, Paal; Johansen, Bertil; Thøgersen, Annett; Diplas, Spyridon; Carvalho, Patricia; Løvvik, Ole Martin; Wright, Daniel Nilsen; Azarov, Alexander; Svensson, Bengt Gunnar (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)
    In this work we present a significant advancement in cubic silicon carbide (3C-SiC) growth in terms of crystal quality and domain size, and indicate its potential use in photovoltaics. To date, the use of 3C-SiC for ...
  • Effectiveness of Neural Networks for Research on Novel Thermoelectric Materials. A Proof of Concept. 
    Remonato, Filippo; Løvvik, Ole Martin; Flage-Larsen, Espen (Chapter / Bokkapittel / AcceptedVersion; Peer reviewed, 2019)
    This paper describes the application of neural network approaches to the discovery of new materials exhibiting thermoelectric properties. Thermoelectricity is the ability of a material to convert energy from heat to ...
  • Enhancement of thermoelectric properties by energy filtering: Theoretical potential and experimental reality in nanostructured ZnSb 
    Berland, Kristian; Song, Xin; Carvalho, Patricia; Persson, Clas; Finstad, Terje; Løvvik, Ole Martin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    Energy filtering has been suggested by many authors as a means to improve thermoelectric properties. The idea is to filter away low-energy charge carriers in order to increase Seebeck coefficient without compromising ...
  • Fabrication of a Silicide Thermoelectric Module Employing Fractional Factorial Design Principles 
    Graff, Joachim Moe; Schuler, Raphael; Song, Xin; Castillo-Hernandez, Gustavo; Skomedal, Gunstein; Enebakk, Erik; Wright, Daniel Nilsen; Stange, Marit Synnøve Sæverud; de Boor, Johannes; Løvvik, Ole Martin; Schrade, Matthias (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Abstract Thermoelectric modules can be used in waste heat harvesting, sensing, and cooling applications. Here, we report on the fabrication and performance of a four-leg module based on abundant silicide materials. While ...
  • Formation of nanoporous Si upon self-organized growth of Al and Si nanostructures 
    Thøgersen, Annett; Jensen, Ingvild Julie Thue; Stange, Marit Synnøve Sæverud; Kjeldstad, Torunn; Martinez-Martinez, Diego; Løvvik, Ole Martin; Ulyashin, Alexander; Diplas, Spyridon (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Nanostructured materials offer unique electronic and optical properties compared to their bulk counterparts. The challenging part of the synthesis is to create a balance between the control of design, size limitations, ...
  • High entropy alloy CrFeNiCoCu sputter deposited films: Structure, electrical properties, and oxidation 
    Mayandi, Jeyanthinath; Schrade, Matthias; Vajeeston, Ponniah; Stange, Marit Synnøve Sæverud; Lind, Anna Maria; Sunding, Martin Fleissner; Deuermeier, Jonas; Fortunato, Elvira; Løvvik, Ole Martin; Ulyashin, Alexander; Diplas, Spyridon; Almeida Carvalho, Patricia; Finstad, Terje Gunnar (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2022)
    High entropy alloy (HEA) films of CrFeCoNiCu were deposited by sputtering. Their structure was characterized and their electric transport properties were studied by temperature-dependent Hall and Seebeck measurements. The ...
  • Investigation of the electrostatic potential of a grain boundary in Y-substituted BaZrO3 using inline electron holography 
    Bondevik, Tarjei; Ness, Heine H.; Bazioti, Kalliopi; Norby, Truls Eivind; Løvvik, Ole Martin; Koch, Christoph T.; Prytz, Øystein (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)
    We apply inline electron holography to investigate the electrostatic potential across an individual BaZr0.9Y0.1O3 grain boundary. With holography, we measure a grain boundary potential of −1.3 V. Electron energy loss ...
  • Jahn-Teller active fluoroperovskites ACrF3 (A=Na+, K+): Magnetic and thermo-optical properties 
    Bernal, Fabian Leonardo Martinez; Lundvall, Fredrik; Kumar, Susmit; Hansen, Per-Anders S.; Wragg, David S.; Fjellvåg, Helmer; Løvvik, Ole Martin (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2021)
    Chromium (II) fluoroperovskites A CrF 3 ( A = Na + , K + ) are strongly correlated Jahn-Teller active materials at low temperatures. In this paper, we examine the role that the A -site ion plays in this family of ...
  • Lattice thermal conductivity of half-Heuslers with density functional theory and machine learning: Enhancing predictivity by active sampling with principal component analysis 
    Tranås, Rasmus André; Løvvik, Ole Martin; Tomic, Oliver; Berland, Kristian (Journal article / Tidsskriftartikkel / SubmittedVersion, 2021)
    Low lattice thermal conductivity is essential for high thermoelectric performance of a material. Lattice thermal conductivity is often computed using density functional theory (DFT), typically at a high computational cost. ...
  • Lattice thermal conductivity of TixZryHf1−x−yNiSn half-Heusler alloys calculated from first principles: Key role of nature of phonon modes 
    Eliassen, Simen Nut Hansen; Katre, Anikta; Madsen, Georg; Persson, Clas; Løvvik, Ole Martin; Berland, Kristian (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    In spite of their relatively high lattice thermal conductivity κℓ, the XNiSn (X=Ti, Zr, or Hf) half-Heusler compounds are good thermoelectric materials. Previous studies have shown that κℓ can be reduced by sublattice ...
  • New structure and insight on the phase transition within the Cu-Pd-Sn system with 25 at. % Sn 
    Amundsen, Monika; Pike, Nicholas; Løvvik, Ole Martin; Almeida Carvalho, Patricia; Gunnæs, Anette Eleonora (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    The Cu-Pd-Sn material system has a (Cu, Pd) 3 Sn phase region that shows an interesting and unexplored marten- sitic phase transformation. Literature on this system is limited and the description of the phases present is ...
  • Oxygen nonstoichiometry in (Ca2CoO3)0.62(CoO2): a combined experimental and computational study 
    Schrade, Matthias; Casolo, Simone; Graham, Paul J.; Ulrich, Clemens; Li, Sean; Løvvik, Ole Martin; Finstad, Terje; Norby, Truls (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2014)
    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 ...
  • Probing the structural evolution and its impact on magnetic properties of FeCoNi(AlMn)x high-entropy alloy at the nanoscale 
    Bazioti, Kalliopi; Løvvik, Ole Martin; Poulia, Anthoula; Almeida Carvalho, Patricia; S. Azar, Amin; Mikheenko, Pavlo; Diplas, Spyridon; Gunnæs, Anette Eleonora (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    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 ...
  • The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X=Hf, Zr, Ti) half-Heusler alloys 
    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 (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Thermoelectric application of half-Heusler compounds suffers from their fairly high thermal conductivities. Insight into how effective various scattering mechanisms are in reducing the thermal conductivity of fabricated ...
  • Structural and magnetic characterization of the elusive Jahn-Teller active NaCrF3 
    Bernal, Fabian Leonardo Martinez; Sottmann, Jonas; Wragg, David; Fjellvåg, Helmer; Fjellvåg, Øystein; Drathen, Christina; Slawinski, Wojciech Andrzej; Løvvik, Ole Martin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    We report on the structural and magnetic properties of the elusive Jahn-Teller active compound NaCrF3, for first time synthesized in large quantities allowing detailed characterization. The crystal structure of NaCrF3 is ...