A5073980747- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Semiconductor materials and devices
- Multiferroics and related materials
- Advanced Condensed Matter Physics
- Ferroelectric and Piezoelectric Materials
- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Advanced Thermoelectric Materials and Devices
- ZnO doping and properties
- Physics of Superconductivity and Magnetism
- Transition Metal Oxide Nanomaterials
- Advanced Battery Technologies Research
- Catalysis and Oxidation Reactions
- Advancements in Solid Oxide Fuel Cells
- Advanced Memory and Neural Computing
- Advanced Materials Characterization Techniques
- Catalytic Processes in Materials Science
- Supercapacitor Materials and Fabrication
- Gas Sensing Nanomaterials and Sensors
- Extraction and Separation Processes
- Semiconductor materials and interfaces
- Acoustic Wave Resonator Technologies
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
University of Twente
2016-2025
National Synchrotron Radiation Laboratory
2023
Chinese Academy of Sciences
2023
University of Science and Technology of China
2023
Nanchang University
2023
Institute of Nanotechnology
2021
Institute of Inorganic Chemistry of the Slovak Academy of Sciences
2010-2019
University of California, Berkeley
2007-2012
Oak Ridge National Laboratory
2011
Defense Advanced Research Projects Agency
2010
Multiferroic materials, or materials that simultaneously possess two more ferroic order parameters, have returned to the forefront of research. Driven by desire achieve new functionalities—such as electrical control ferromagnetism at room temperature—researchers undertaken a concerted effort identify and understand complexities multiferroic materials. The ability create high quality thin film multiferroics stands one single most important landmarks in this flurry research activity. In review...
Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ films with thicknesses from 3 to 70 unit cells resulted in the identification a lower critical thickness for nonmetallic nonferromagnetic layer at interface ${\text{SrTiO}}_{3}$ (001) substrate only three $(\ensuremath{\sim}12\text{ }\text{\AA{}})$. Furthermore, linear-dichroism demonstrate presence preferred...
We report the formation of a novel ferromagnetic state in antiferromagnet ${\mathrm{BiFeO}}_{3}$ at interface with ferromagnet ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$. Using x-ray magnetic circular dichroism Mn and Fe ${L}_{2,3}$ edges, we discovered that development this spin structure is strongly associated onset significant exchange bias. Our results demonstrate directly related to an electronic orbital reconstruction interface, which supported by linearly polarized...
Epitaxial oxide interfaces with broken translational symmetry have emerged as a central paradigm behind the novel behaviors of superlattices. Here, we use scanning transmission electron microscopy to demonstrate direct, quantitative unit-cell-by-unit-cell mapping lattice parameters and oxygen octahedral rotations across ${\mathrm{BiFeO}}_{3}\mathrm{\text{\ensuremath{-}}}{\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ interface elucidate how change crystal is accommodated. Combined...
Abstract A large variety of transport properties have been observed at the interface between insulating oxides SrTiO 3 and LaAlO such as insulation, 2D metallicity, 3D bulk magnetic scattering, superconductivity. The relation structure /LaAlO can be explained in a meaningful way by taking into account relative contribution three structural aspects: oxygen vacancies, deformations (including cation disorder), electronic reconstruction. emerging phase diagram is much richer than for related due...
Conventional two-dimensional electron gases are realized by engineering the interfaces between semiconducting compounds. In 2004, Ohtomo and Hwang discovered that an gas can be also at interface large gap insulators made of transition metal oxides [1]. This finding has generated considerable efforts to clarify underlying microscopic mechanism. Of particular interest is LaAlO3/SrTiO3 system, because it features especially striking properties. High carrier mobility [1], electric field tuneable...
Giant photovoltaic effect due to bulk observed in multiferroic BiFeO3 thin films has triggered a renewed interest on photoferroelectric materials for applications. Tremendous advance been done improve power conversion efficiency (up up 8.1%) photoferroelectrics via absorption increase using narrow bandgap ferroelectrics. Other strategies, as it is the more efficient use of ferroelectric internal electric field, are ongoing. Moreover, by-product, several progress have also achieved...
We demonstrate a direct correlation between the domain structure of multiferroic BiFeO3 thin films and exchange bias Co 0.9Fe 0.1/BiFeO3 heterostructures. Two distinct types interactions - an enhancement coercive field ( enhancement) combined with large shifts hysteresis loop bias) have been observed in these heterostructures, which depend directly on type crystallography nanoscale approximately 2 nm) walls film. show that magnitude interaction scales length 109 degrees ferroelectric BiFeO 3...
Ferroelectric size effects in multiferroic BiFeO3 have been studied using a host of complementary measurements. The structure such epitaxial films has investigated atomic force microscopy, transmission electron and x-ray diffraction. crystal the identified as monoclinic phase, which suggests that polarization direction is close to ⟨111⟩. Such behavior also confirmed by piezoforce microscopy That reveals ferroelectricity down at least 2nm.
We present a study of the thickness dependence magnetism and electrical conductivity in ultrathin ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}{\mathrm{MnO}}_{3}$ films grown on ${\mathrm{SrTiO}}_{3}$ (110) substrates. found critical 10 unit cells below which disappeared simultaneously Curie temperature increased, indicating magnetic insulating phase at room temperature. These samples have about 560 K with significant saturation magnetization...
In this paper, an overview of the fabrication and properties high-quality La 0.67 Sr 0.33 MnO 3 (LSMO) thin films is given. A LSMO film combines a smooth surface morphology with large magnetization small residual resistivity, while avoiding precipitates segregation. literature, typically only few these issues are adressed. We therefore present thorough characterization our films, which were grown by pulsed laser deposition. The characterized reflection high energy electron diffraction,...
The synthesis of materials with well-controlled composition and structure improves our understanding their intrinsic electrical transport properties. Recent developments in atomically controlled growth have been shown to be crucial enabling the study new physical phenomena epitaxial oxide heterostructures. Nevertheless, these can influenced by presence defects that act as extrinsic sources both doping impurity scattering. Control over nature density such is therefore necessary, are we fully...
Abstract Fast charging is one of the key requirements for next‐generation lithium‐ion batteries, however, diffusion rates typical electrode materials are limited. Nanosizing active material a common strategy to increase effective transport rate, but it also decreases volumetric energy/power density and stability battery. In this work, nickel niobate NiNb 2 O 6 demonstrated first time as new intrinsic high‐rate anode batteries without requirement realizing nano‐architectures. The host crystal...
Wadsley-Roth phase titanium niobium oxides have received considerable interest as anodes for lithium ion batteries. However, the volume expansion and sluggish ion/electron transport kinetics retard its application in grid scale. Here, fast durable storage entropy-stabilized Fe0.4 Ti1.6 Nb10 O28.8 (FTNO) is enabled by tuning entropy via Fe substitution. By increasing entropy, a reduction of calcination temperature to form pure material achieved, leading reduced grain size and, therefore,...
The perovskite SrTiO3-LaAlO3 structure has advanced to a model system investigate the rich electronic phenomena arising at polar oxide interfaces. Using first principles calculations and transport measurements we demonstrate that an additional SrTiO3 capping layer prevents atomic reconstruction LaAlO3 surface triggers significantly lower film thickness than for uncapped systems. Combined theoretical experimental evidence (from magnetotransport ultraviolet photoelectron spectroscopy) suggests...
We report significant thermal conductivity reduction in oxygen-deficient lanthanum-doped strontium titanate (Sr1−xLaxTiO3−δ) films as compared to unreduced titanates. Our experimental results suggest that the oxygen vacancies could have played an important role reduction. This be due nature of randomly distributed and clustered vacancies, which would very effective scatter phonons. provide a pathway for tailoring complex oxides, is beneficial various applications including thermoelectrics.
Direct atomic displacement mapping at ferroelectric interfaces by aberration corrected scanning transmission electron microscopy(STEM) (a-STEM image, b-corresponding profile) is combined with Landau-Ginsburg-Devonshire theory to obtain the complete interface electrostatics in real space, including separate estimates for polarization and intrinsic charge contributions. Detailed facts of importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but...
Distinct MnO6 octahedral distortions near and away from the La0.67Sr0.33MnO3/SrTiO3(001) (LSMO/STO) interface are quantified using synchrotron x-ray diffraction dynamical simulations. Three structural regions of stress accommodation throughout film thickness were resolved: LSMO/STO interface, intermediate region farther main layer interface. The results show that within first two unit cells is accommodated by suppression rotations in film, leading to expansion c-axis lattice parameter....
Abstract Perovskite oxide heteroepitaxy receives much attention because of the possibility to combine diverse functionalities perovskite building blocks. A general boundary condition for epitaxy is presence polar discontinuities at heterointerfaces. These result in reconstructions, often creating new interface. However, a significant number materials these reconstructions are unwanted as they alter intrinsic properties Therefore, strategy eliminate this reconstruction discontinuity...