• Anisotropic in-plane dielectric and ferroelectric properties of tensile-strained BaTiO3 films with three different crystallographic orientations 

      Ræder, Trygve Magnus; Holstad, Theodor Secanell; Nylund, Inger-Emma; Glaum, Julia; Einarsrud, Mari-Ann; Meier, Dennis; Grande, Tor (Peer reviewed; Journal article, 2021)
      Ferroelectric properties of films can be tailored by strain engineering, but a wider space for property engineering can be opened by including crystal anisotropy. Here, we demonstrate a huge anisotropy in the dielectric ...
    • 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 ...
    • Contact-free reversible switching of improper ferroelectric domains by electron and ion irradiation 

      Roede, Erik Dobloug; Mosberg, Aleksander Buseth; Evans, Donald; Bourret, Edith; Yan, Zewu; Van Helvoort, Antonius; Meier, Dennis (Peer reviewed; Journal article, 2021)
      Focused ion beam (FIB) and scanning electron microscopy (SEM) are used to reversibly switch improper ferroelectric domains in the hexagonal manganite ErMnO3. Surface charging is achieved by local ion (positive charging) ...
    • Defect chemistry and ferroelectric domain walls in hexagonal manganites 

      Småbråten, Didrik René (Doctoral theses at NTNU;2018:263, Doctoral thesis, 2018)
      The hexagonal manganites h-RMnO3 (R=Y, In, Sc, Ho-Lu) have been studied the last two decades for their exotic and diverse functional properties. Their large chemical flexibility makes this material class an ideal chemical ...
    • 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, ...
    • Domain-Pattern Transfer across an Artificial Magnetoelectric Interface 

      De Luca, Gabriele; Schoenherr, Peggy; Mendil, Johannes; Meier, Dennis; Fiebig, Manfred; Trassin, Morgan (Journal article; Peer reviewed, 2018)
      Magnetoelectric interfaces provide efficient pathways for manipulating the magnetic order with low-power-consuming electric fields. A prime example of this is the voltage-controlled domain-pattern transfer from a multiferroic ...
    • Electrical half-wave rectification at ferroelectric domain walls 

      Schaab, Jakob; Skjærvø, Sandra Helen; Krohns, Stephan; Dai, Xiaoyu; Holtz, Megan, E.; Cano, Andrés; Lilienblum, Martin; Yan, Zewu; Bourret, Edith; Muller, David A.; Fiebig, Manfred; Selbach, Sverre Magnus; Meier, Dennis (Journal article; Peer reviewed, 2018)
      Domain walls in ferroelectric semiconductors show promise as multifunctional two-dimensional elements for next-generation nanotechnology. Electric fields, for example, can control the direct-current resistance and reversibly ...
    • 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, ...
    • Electrostatic potential mapping at ferroelectric domain walls by low-temperature photoemission electron microscopy 

      Schaab, Jakob; Shapovalov, Konstantin; Schoenherr, Peggy; Hackl, Johanna; Khan, Muhammad Imtiaz; Hentschel, Mario; Yan, Zewu; Bourret, Edith; Schneider, Claus M.; Nemsak, Slavomír; Stengel, Massimiliano; Cano, Andrés; Meier, Dennis (Journal article; Peer reviewed, 2019)
      Low-temperature X-ray photoemission electron microscopy (X-PEEM) is used to measure the electric potential at domain walls in improper ferroelectric Er0.99Ca0.01MnO3. By combining X-PEEM with scanning probe microscopy and ...
    • Emergent nanoscale functionality in uniaxial ferroelectrics 

      Holstad, Theodor Secanell (Doctoral theses at NTNU;2020:138, Doctoral thesis, 2020)
      This thesis has been focused on the characterization and manipulation of the electronic nanoscale properties of domains and domain walls in uniaxial ferroelectrics. Two classes of uniaxial ferroelectrics have been investigated, ...
    • FIB lift-out of conducting ferroelectric domain walls in hexagonal manganites 

      Mosberg, Aleksander Buseth; Roede, Erik Dobloug; Evans, Donald; Holstad, Theodor S.; Bourret, Edith; Yan, Zewu; Van Helvoort, Antonius; Meier, Dennis (Journal article; Peer reviewed, 2019)
      A focused ion beam (FIB) methodology is developed to lift out suitable specimens containing charged domain walls in improper ferroelectric ErMnO3. The FIB procedure allows for extracting domain wall sections with well-defined ...
    • FIB lift-out of conducting ferroelectric domain walls in hexagonal manganites 

      Evans, Donald; Meier, Dennis; Mosberg, Aleksander Buseth; Roede, Erik Dobloug; Holstad, Theodor S.; Bourret, Edith; Yan, Zewu; Van Helvoort, Antonius (Journal article; Peer reviewed, 2019)
      A focused ion beam (FIB) methodology is developed to lift out suitable specimens containing charged domain walls in improper ferroelectric ErMnO3. The FIB procedure allows for extracting domain wall sections with well-defined ...
    • 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) ...
    • Frequency dependent polarisation switching in h-ErMnO3 

      Ruff, Alexander; Li, Ziyu; Loidl, Alois; Schaab, Jakob; Fiebig, Manfred; Cano, Andres; Yan, Zewu; Bourret, Edith; Glaum, Julia; Meier, Dennis; Krohns, Stephan (Journal article; Peer reviewed, 2018)
      We report an electric-field poling study of the geometric-driven improper ferroelectric h-ErMnO3. From a detailed dielectric analysis we deduce the temperature and frequency dependent range for which single-crystalline ...
    • Global formation of topological defects in the multiferroic hexagonal manganites 

      Meier, Quintin Noel; Lilienblum, Martin; Griffin, Sinead M; Conder, K; Pomjakushina, Ekaterina; Yan, Zewu; Bourret, Edith; Meier, Dennis; Lichtenberg, Frank; Salje, Ekhard K. H.; Spaldin, Nicola A.; Fiebig, Manfred; Cano, Andrés (Journal article; Peer reviewed, 2017)
      The spontaneous transformations associated with symmetry-breaking phase transitions generate domain structures and defects that may be topological in nature. The formation of these defects can be described according to the ...
    • Local dynamics of topological magnetic defects in the itinerant helimagnet FeGe 

      Dussaux, Antoine; Schoenherr, Peggy; Koumpouras, Konstantinos; Chico, Jonathan; Chang, Kevin; Lorenzelli, Luca; Kanazawa, Naoya; Tokura, Yoshinori; Garst, Markus; Bergman, Anders; Degen, Christian L.; Meier, Dennis (Journal article; Peer reviewed, 2016)
      Chiral magnetic interactions induce complex spin textures including helical and conical spin spirals, as well as particle-like objects such as magnetic skyrmions and merons. These spin textures are the basis for innovative ...
    • Magnetoelectric force microscopy on antiferromagnetic 180 degree domains in Cr2O3 

      Schoenherr, Peggy; Giraldo, L. M.; Lilienblum, Martin; Trassin, Morgan; Meier, Dennis; Fiebig, Manfred (Journal article; Peer reviewed, 2017)
      Magnetoelectric force microscopy (MeFM) is characterized as methodical tool for the investigation of antiferromagnetic domain states, in particular of the 180 ∘ variety. As reference compound for this investigation we use ...
    • Magnetoelectric inversion of domain patterns 

      Leo, Naemi; Carolus, Vera; White, Jonathan S.; Kenzelmann, Michel; Hudl, Matthias; Tolédano, Pierre; Honda, T.; Kimura, Tsuyoshi; Ivanov, S. A.; Weil, M.; Lottermoser, Thomas; Meier, Dennis; Fiebig, Manfred (Journal article; Peer reviewed, 2018)
      The inversion of inhomogeneous physical states has great technological importance; for example, active noise reduction relies on the emission of an inverted sound wave that interferes destructively with the noise of the ...
    • Measuring ferroelectric order parameters at domain walls and vortices in hexagonal manganites with atomic resolution STEM 

      Holtz, Megan, E.; Shapovalov, Konstantin; Mundy, Julia; Chang, C. S.; Meier, Dennis; Cano, Andrés; Muller, David A. (Journal article; Peer reviewed, 2017)