Blar i SINTEF Open på forfatter "Løvvik, Ole Martin"
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Application of machine learning-based selective sampling to determine BaZrO3 grain boundary structures
Bondevik, Tarjei; Kuwabara, Akihide; Løvvik, Ole Martin (Peer reviewed; Journal article, 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 (Peer reviewed; Journal article, 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, ... -
Calculation of the anisotropic coefficients of thermal expansion: A first-principles approach
Pike, Nicholas; Løvvik, Ole Martin (Journal article; 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 ... -
Comparing electrochemical perormance of transition metal silicate cathodes and chevrel phase Mo6S8 in the analogous rechargeable Mg-ion battery system
Chen, Xinzhi; Bleken, Francesca Lønstad; Løvvik, Ole Martin; Vullum-Bruer, Fride (Peer reviewed; Journal article, 2016)Polyanion based silicate materials, MgMSiO4 (M = Fe, Mn, Co), previously reported to be promising cathode materials for Mg-ion batteries, have been re-examined. Both the sol-gel and molten salt methods are employed to ... -
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 (Peer reviewed; Journal article, 2021)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 (Peer reviewed; Journal article, 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 ... -
Discarded gems: Thermoelectric performance of materials with band gap emerging at the hybrid-functional level
Berland, Kristian; Løvvik, Ole Martin; Tranås, Rasmus André (Peer reviewed; Journal article, 2021)A finite electronic band gap is a standard filter in high-throughput screening of materials using density functional theory (DFT). However, because of the systematic underestimation of band gaps in standard DFT approximations, ... -
Discovering Thermoelectric Materials Using Machine Learning: Insights and Challenges
Tabib, Mandar; Løvvik, Ole Martin; Johannessen, Kjetil Andre; Rasheed, Adil; Sagvolden, Espen; Rustad, Anne Marthine (Journal article; Peer reviewed, 2018)This work involves the use of combined forces of data-driven machine learning models and high fidelity density functional theory for the identification of new potential thermoelectric materials. The traditional method of ... -
Electronic packaging for harsh environments
Larsson, Andreas; Tollefsen, Torleif Andre; Løvvik, Ole Martin; Aasmundtveit, Knut Eilif (Lecture, 2016) -
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; 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 ... -
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; 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 (Peer reviewed; Journal article, 2021)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 previously ... -
Grain boundary segregation in Pd-Cu-Ag alloys for high permeability hydrogen separation membranes
Løvvik, Ole Martin; Zhao, Dongdong; Li, Yanjun; Bredesen, Rune; Peters, Thijs (Peer reviewed; Journal article, 2018)Dense metal membranes that are based on palladium (Pd) are promising for hydrogen separation and production due to their high selectivity and permeability. Optimization of alloy composition has normally focused on bulk ... -
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 (Peer reviewed; Journal article, 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 ... -
High-Performance Nano Insulation Materials for Energy-Efficient Buildings
Jelle, Bjørn Petter; Tilset, Bente Gilbu; Gao, Tao; Grandcolas, Mathieu; Løvvik, Ole Martin; Bohne, Rolf André; Alex Mofid, Sohrab; Ng, Serina; Sagvolden, Espen (Lecture, 2017)High-performance nano insulation materials (Hi-Per NIM) may be developed by exploiting the Knudsen effect for reduced thermal conductivity and thus make thermal insulation materials with a nanoporous air-filled structure. ... -
Hydrogen Induced Vacancy Clustering and Void Formation Mechanisms at Grain Boundaries in Palladium
Polfus, Jonathan Marc; Løvvik, Ole Martin; Bredesen, Rune; Peters, Thijs (Peer reviewed; Journal article, 2020)Hydrogen has a significant impact on the formation of vacancies, clusters and voids in palladium and other metals. The formation of vacancy-hydrogen complexes in bulk Pd and at Σ3 and Σ5 grain boundaries was investigated ... -
Interface phenomena in magnetron sputtered Cu2O/ZnO heterostructures
Jensen, Ingvild Julie Thue; Gorantla, Sandeep Madhukar; Løvvik, Ole Martin; Gan, Jiantuo; Nguyen, Phuong Dan; Monakhov, Edouard; Svensson, Bengt Gunnar; Gunnæs, Anette Eleonora; Diplas, Spyridon (Peer reviewed; Journal article, 2017)The interface between ZnO and Cu2O has been predicted to be a good candidate for use in thin film solar cells. However, the high predicted conversion efficiency has yet to be fully realized experimentally. To explore the ... -
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 (Peer reviewed; Journal article, 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 (Peer reviewed; Journal article, 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. ... -
Mapping the chemistry within, and the strain around, Al-alloy precipitates at atomic resolution by multi-frame scanning transmission electron microscopy
Jones, Lewys; Wenner, Sigurd; Nord, Magnus Kristofer; Ninive, Per Harald; Løvvik, Ole Martin; Marioara, Calin Daniel; Holmestad, Randi; Nellist, Peter (Peer reviewed; Journal article, 2017)