• A new material for oxygen-permeable membranes 

      Adnan, Mohammed Mostafa (Master thesis, 2017)
      In this study, hexagonal YMnO3 doped with 15% Ti was used in the preparation of an asymmetric oxygen permeable membrane. Several different methods for the fabrication of the asymmetric membrane have been used, and the ...
    • Application of a long short-term memory for deconvoluting conductance contributions at charged ferroelectric domain walls 

      Holstad, Theodor Secanell; Ræder, Trygve Magnus; Evans, Donald; Småbråten, Didrik Rene; Krohns, Stephan; Schaab, Jakob; Yan, Zewu; Bourret, Edith; Helvoort, Antonius T. J. van; Grande, Tor; Selbach, Sverre Magnus; Agar, Joshua; Meier, Dennis Gerhard (Peer reviewed; Journal article, 2020)
      Ferroelectric domain walls are promising quasi-2D structures that can be leveraged for miniaturization of electronics components and new mechanisms to control electronic signals at the nanoscale. Despite the significant ...
    • Charged domain walls in improper ferroelectric hexagonal manganites and gallates 

      Småbråten, Didrik Rene; Meier, Quintin Noel; Skjærvø, Sandra Helen; Inzani, Katherine; Meier, Dennis; Selbach, Sverre Magnus (Journal article; Peer reviewed, 2018)
      Ferroelectric domain walls are attracting broad attention as atomic-scale switches, diodes and mobile wires for next-generation nanoelectronics. Charged domain walls in improper ferroelectrics are particularly interesting ...
    • Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide 

      Evans, Donald; Holstad, Theodor Secanell; Mosberg, Aleksander Buseth; Småbråten, Didrik Rene; Vullum, Per Erik; Dadlani, Anup; Shapovalov, Konstantin; Yan, Zewu; Bourret, Edith; Gao, David Zhe; Akola, Jaakko; Torgersen, Jan; Van Helvoort, Antonius; Selbach, Sverre Magnus; Meier, Dennis (Peer reviewed; Journal article, 2020)
      Utilizing quantum effects in complex oxides, such as magnetism, multiferroicity and superconductivity, requires atomic-level control of the material’s structure and composition. In contrast, the continuous conductivity ...
    • Defect-Enhanced Polarization Switching in the Improper Ferroelectric LuFeO3 

      Barrozo, Petrucio; Småbråten, Didrik Rene; Tang, Yun-Long; Prasad, Bhagwati; Saremi, Sahar; Ozgur, Rustem; Thakare, Vishal; Steinhardt, Rachel A.; Holtz, Megan, E.; Stoica, Vladimir Alexandru; Martin, Lane W.; Schlom, Darrel G.; Selbach, Sverre Magnus; Ramesh, Ramamoorthy (Peer reviewed; Journal article, 2020)
      Results of switching behavior of the improper ferroelectric LuFeO3 are presented. Using a model set of films prepared under controlled chemical and growth‐rate conditions, it is shown that defects can reduce the quasi‐static ...
    • Domain wall mobility and roughening in doped ferroelectric hexagonal manganites 

      Småbråten, Didrik Rene; Holstad, Theodor Secanell; Evans, Donald; Zewu, Yan; Bourret, Edith; Meier, Dennis; Selbach, Sverre Magnus (Peer reviewed; Journal article, 2020)
      The macroscopic performance of ferroelectric and piezoelectric devices depends strongly on domain wall dynamics. It is clear that structural defects, such as vacancies, interstitials, and dopants codetermine the dynamics, ...
    • Electronic bulk and domain wall properties in B-site doped hexagonal ErMnO3 

      Holstad, Theodor S.; Evans, Donald; Ruff, Alexander; Småbråten, Didrik Rene; Schaab, Jakob; Tzschaschel, Christian; Yan, Zewu; Bourret, Edith; Selbach, Sverre Magnus; Krohns, Stephan; Meier, Dennis (Journal article; Peer reviewed, 2018)
      Acceptor and donor doping is a standard for tailoring semiconductors. More recently, doping was adapted to optimize the behavior at ferroelectric domain walls. In contrast to more than a century of research on semiconductors, ...
    • First-principles study of topologically protected vortices and ferroelectric domain walls in hexagonal YGaO3 

      Småbråten, Didrik Rene; Nakata, Ayako; Meier, Dennis; Miyazaki, Tsuyoshi; Selbach, Sverre Magnus (Peer reviewed; Journal article, 2020)
      Ferroelectric behavior on the meso- and macroscopic scale depends on the formation and dynamics of domains and controlling the domain patterns is imperative to device performance. While density functional theory (DFT) ...
    • Intrinsic and extrinsic conduction contributions at nominally neutral domain walls in hexagonal manganites 

      Schultheiß, Jan; Schaab, Jakob; Småbråten, Didrik Rene; Skjærvø, Sandra Helen; Bourret, Edith; Yan, Zewu; Selbach, Sverre Magnus; Meier, Dennis Gerhard (Peer reviewed; Journal article, 2020)
      Conductive and electrostatic atomic force microscopy (cAFM and EFM) are used to investigate the electric conduction at nominally neutral domain walls in hexagonal manganites. The EFM measurements reveal a propensity of ...
    • Modeling of electrochemical and photoelectrochemical impedance functions for films 

      Småbråten, Didrik Rene (Master thesis, 2014)
      The aim of this study was to develop mathematical models for electrochemical and photoelectrochemical impedance transfer functions for mixed conducting films. These models include electrochemical impedance spectroscopy ...
    • Oxygen vacancies in the bulk and at neutral domain walls in hexagonal YMnO3 

      Skjærvø, Sandra Helen; Småbråten, Didrik Rene; Spaldin, Nicola A; Tybell, Per Thomas Martin; Selbach, Sverre Magnus (Journal article; Peer reviewed, 2018)
      We use density functional calculations to investigate the accommodation and migration of oxygen vacancies in bulk hexagonal YMnO3, and to study interactions between neutral ferroelectric domain walls and oxygen vacancies. ...
    • Pure and Zr-doped YMnO3+δ as a YSZ-compatible SOFC cathode: a combined computational and experimental approach 

      Botello, Zulma L. Moreno; Montenegro, Alejandra; Osorio, Nicolas Grimaldos; Huve, Marielle; Pirovano, Caroline; Småbråten, Didrik Rene; Selbach, Sverre Magnus; Caneiro, Alberto; Roussel, Pascal; Gauthier, Gilles H. (Journal article; Peer reviewed, 2019)
      A thorough study of the Y1−xZrxMnO3+δ series is presented with the objective to use these materials as SOFC cathodes. These pure and Zr-doped yttrium manganites exhibit a layered hexagonal structure similar to a peculiar ...
    • Tailoring the electrical conductivity and hardening in BiFeO3 ceramics 

      Makarovič, Maja; Kanas, Nikola; Zorko, A.; Ziberna, K.; Ursic, H.; Småbråten, Didrik Rene; Selbach, Sverre Magnus; Tadej, Rojac (Peer reviewed; Journal article, 2020)
      In this report, the influence of cobalt doping and annealing atmosphere on the electrical conductivity and polarization switching of BiFeO3 (BFO) ceramics was studied. Electrical conductivity as well as hardening behavior ...
    • Very sharp diffraction peak in nonglass-forming liquid with the formation of distorted tetraclusters 

      Koyama, Chihiro; Tahara, Shuta; Kohara, Shinji; Onodera, Yohei; Småbråten, Didrik Rene; Selbach, Sverre Magnus; Akola, Jaakko; Ishikawa, Takehiko; Masuno, Atsunobu; Mizuno, Akitoshi; Okada, Junpei T.; Watanabe, Yuki; Nakata, Yui; Ohara, Koji; Tamaru, Haruka; Oda, Hirohisa; Obayashi, Ippei; Hiraoka, Yasuyuki; Sakata, Osami (Peer reviewed; Journal article, 2020)
      Understanding the liquid structure provides information that is crucial to uncovering the nature of the glass-liquid transition. We apply an aerodynamic levitation technique and high-energy X-rays to liquid (l)-Er2O3 to ...