A5034583001- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Electronic and Structural Properties of Oxides
- Multiferroics and related materials
- Perovskite Materials and Applications
- Ferroelectric and Piezoelectric Materials
- Nonlinear Optical Materials Research
- Solid-state spectroscopy and crystallography
- Ferroelectric and Negative Capacitance Devices
- Advanced Data Storage Technologies
- ZnO doping and properties
- Catalysis and Oxidation Reactions
- Semiconductor materials and devices
- Catalytic Processes in Materials Science
- Advanced Memory and Neural Computing
Norwegian University of Science and Technology
2015-2021
Silicon Labs (Norway)
2021
University of California, Davis
2017
Lawrence Berkeley National Laboratory
2017
An oxygen vacancy driven structural response at the epitaxial interface between La0.7Sr0.3MnO3 films and SrTiO3 substrates is reported. A combined scanning transmission electron microscopy energy loss spectroscopy study reveal presence of an elongated out-of-plane lattice parameter, coupled to vacancies reduced manganese oxidation state side interface. Density functional theory calculations support that measured structure a disordered deficient brownmillerite structure. The effect mobility...
We observe an induced switchable magnetic moment of $1.6\ifmmode\pm\else\textpm\fi{}0.40\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}/\mathrm{Fe}$ for the nominally antiferromagnetic $\mathrm{LaFe}{\mathrm{O}}_{3}$ extending two to four interface layers into non--charge transfer system $\mathrm{L}{\mathrm{a}}_{0.7}\mathrm{S}{\mathrm{r}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}\text{/}\mathrm{LaFe}{\mathrm{O}}_{3}\text{/}\mathrm{SrTi}{\mathrm{O}}_{3}(111)$. Simultaneously a mismatch...
Determining the three-dimensional (3D) crystallography of a material with subnanometer resolution is essential to understanding strain effects in epitaxial thin films. A scanning transmission electron microscopy imaging technique demonstrated that visualizes presence and strength atomic movements leading period doubling unit cell along beam direction, using intensity an extra Laue zone ring back focal plane recorded pixelated detector method. This method used together conventional...
The structural and electronic response of $\mathrm{LaAl}{\mathrm{O}}_{3}$ to biaxial strain in the (111) plane is studied by density functional theory (DFT) compared with (001) isostatic strain. For strain, in-plane rotations are stabilized compressive out-of-plane tensile This an opposite splitting modes Furthermore, for degenerate respect rotation axis, giving rise Goldstone-like modes. We rationalize these changes octahedral analyzing ${V}_{A}/{V}_{B}$ polyhedral volume ratios. Finally,...
Goldstone modes are massless particles resulting from spontaneous symmetry breaking. Although such found in elementary particle physics as well condensed matter systems like superfluid helium, superconductors and magnons - structural rare. Epitaxial strain thin films can induce structures properties not accessible bulk has been intensively studied for (001)-oriented perovskite oxides. Here we predict Goldstone-like phonon (111)-strained SrMnO3 by first-principles calculations. Under...
Perovskite oxides are known for their strong structure property coupling and functional properties such as ferromagntism, ferroelectricity high temperature superconductivity. While the effect of ordered cation vacancies on have been much studied, possibility tuning functionality through anion vacancy ordering has received less attention. Oxygen in ferromagnetic La0.7Sr0.3MnO3-δ thin films recently shown to accumulate close interfaces form a brownmillerite (ABO2.5). This alternating oxygen...
In antiferromagnetic spintronics control of the domains and corresponding spin axis orientation is crucial for devices. Here we investigate in (111)-oriented LaFeO3/SrTiO3, which coupled to structural twin domains. The have either orthorhombic a- or b-axis along in-plane ⟨11¯0⟩ cubic directions substrate, magnetic sample plane. Six degenerate axes are found ⟨112¯⟩ directions. This contrast biaxial anisotropy (001)-oriented films reflects how crystal can be used antiferromagnets.
Strain-phonon coupling, in terms of the shift phonon frequencies under biaxial strain, is studied by density functional theory calculations for 20 perovskite oxides strained their (111) and (001) planes. While strain-phonon coupling strain follows established, intuitive trends, response to more complex. Here we show that can be rationalized Goldschmidt tolerance factor formal cation oxidation states. The established trends between in-phase out-of-phase octahedral rotational modes as well...
Engineering of emergent properties at oxide interfaces is an exciting route towards realizing electronics. Such are often the result a balance between cooperating and competing mechanisms in materials which difficult to decouple. In this paper, we address interplay antiferromagnetic spin axis occurrence magnetic reconstructions (111)-oriented $\mathrm{L}{\mathrm{a}}_{0.7}\mathrm{S}{\mathrm{r}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}/\mathrm{LaFe}{\mathrm{O}}_{3}$ interface. We report critical...
Rotations and distortions of oxygen octahedra in perovskites play a key role determining their functional properties. Here, we investigate how octahedral rotations can couple from one material to another La2/3Sr1/3MnO3/SrTiO3 epitaxial heterostructures by first principles density theory calculations, emphasizing the important differences between systems oriented perpendicular (111)- (001)-facets. We find that coupling length out-of-phase is independent crystalline facet, pointing toward...
Antiferromagnetic thin films typically exhibit a multi-domain state, and control of the antiferromagnetic N\'eel vector is challenging as materials are robust to magnetic perturbations. By relying on anisotropic in-plane strain engineering epitaxial prototypical material LaFeO3, uniaxial demonstrated. Orthorhombic (011)- (101)-oriented DyScO3, GdScO3 NdGaO3 substrates used engineer different states. The stabilises structurally monodomain monoclinic LaFeO3 films. found along tensile strained...