A5056631722- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Multiferroics and related materials
- Electronic and Structural Properties of Oxides
- Magnetic Properties and Applications
- Heusler alloys: electronic and magnetic properties
- Physics of Superconductivity and Magnetism
- Semiconductor materials and devices
- Ferroelectric and Piezoelectric Materials
- Magnetic Properties of Alloys
- Gas Sensing Nanomaterials and Sensors
- ZnO doping and properties
- Rare-earth and actinide compounds
- MXene and MAX Phase Materials
- Analytical Chemistry and Sensors
- Force Microscopy Techniques and Applications
- Quantum and electron transport phenomena
- Electrochemical Analysis and Applications
- Microfluidic and Bio-sensing Technologies
- Orbital Angular Momentum in Optics
- Electron and X-Ray Spectroscopy Techniques
- Advanced Materials Characterization Techniques
- Micro and Nano Robotics
- Advanced Chemical Sensor Technologies
University of Alabama
2016-2025
Arkema (United States)
2023
Center for Information Technology
2016-2017
Tuscaloosa City Schools
2016-2017
The Ohio State University
2008-2016
California NanoSystems Institute
2014-2016
University of California, Santa Barbara
2012-2016
Infineon Technologies (Germany)
2002
UV-visible absorption and cathodoluminescence spectra of phase-pure epitaxial BiFeO3 thin films grown on SrTiO3(001) substrates by ultrahigh vacuum sputtering reveal a bandgap 2.69–2.73eV for highly strained ∼70nm thick films. This value agrees with theoretical calculations recent experimental results films, demonstrating only minimal change lattice distortion. Both show defect transitions at 2.20 2.45eV, which the latter can be attributed to states due oxygen vacancies.
Resistances that exceed the Mott-Ioffe-Regel limit (known as bad metal behavior) and non-Fermi liquid behavior are ubiquitous features of normal state many strongly correlated materials. We establish conditions lead to phases in NdNiO3, which exhibits a prototype bandwidth-controlled metal-insulator transition. show resistance saturation is determined by magnitude Ni eg orbital splitting, can be tuned strain epitaxial films, causing appearance under certain conditions. The results shed light...
We present a multiplex method, based on microscopic programmable magnetic traps in zigzag wires patterned platform, to simultaneously apply directed forces multiple fluid-borne cells or biologically inert microparticles nanoparticles. The gentle tunable do not produce damage and retain cell viability. technique is demonstrated with T-lymphocyte remotely manipulated (by joystick) along desired trajectories silicon surface average speeds up $20\text{ }\text{ }\ensuremath{\mu}\mathrm{m}/\mathrm{s}$.
We demonstrate tuning of magnetocrystalline anisotropy in high-quality Sr(2)FeMoO(6) epitaxial films over a range several thousand Gauss using strain induced by growth on substrates varying lattice constants. Spectroscopic measurements reveal striking, linear dependence the out-of-plane strain-induced tetragonal distortion lattice. This can be tuned from +2000 to -3300 Oe, sufficient rotate easy axis plane out plane. Combined with its half-metallicity and high Curie temperature, this result...
Phase-pure, fully epitaxial ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$ films with a high degree of Fe/Mo ordering have been fabricated using ultrahigh vacuum sputtering and verified by variety techniques. Through identifying controlling critical factors, such as stoichiometry, phase purity, double-perovskite ordering, that complicate the growth films, we demonstrate characteristics high-quality not shown before. Our results include first report distinct magnetic shape anisotropy via scanning...
We report growth of Sr${}_{2}$CrReO${}_{6}$ epitaxial films with 99$%$ Cr/Re ordering and crystalline perfection comparable to those high-quality semiconductor films. The show a Curie temperature 508 K saturation magnetization 1.29 ${\ensuremath{\mu}}_{\mathrm{B}}$ per formula unit, which confirms the presence strong spin-orbit coupling. Unexpectedly, electrical transport optical absorption measurements indicate that is band gap 0.21 eV. unique combination high ferrimagnetism...
The interplay of film stoichiometry and strain on the metal-insulator transition (MIT) Hall coefficient NdNiO3 films grown under different conditions is investigated. Unstrained lattice parameters mismatch strains are evaluated for a range growth pressures substrates. It shown that both temperature MIT in metallic phase highly sensitive to strain. In with lower oxygen/total pressures, very large compressive in-plane can be obtained, which act suppress MIT. Both relatively insensitive...
Confirming the origin of Gilbert damping by experiment has remained a challenge for many decades, even simple ferromagnetic metals. Here, we experimentally identify that increases with decreasing electronic scattering in epitaxial thin films pure Fe. This observation conductivitylike damping, which cannot be accounted classical eddy-current loss, is excellent quantitative agreement theoretical predictions due to intraband scattering. Our results resolve long-standing question about...
Antimony chalcogenide Sb 2 Se 3 is an emerging photovoltaic absorber due to its appropriate bandgap (≈1.1 eV), high absorption coefficient (>10 5 cm −1 ), suitable p‐type conductivity, low toxicity, earth abundance, and excellent stability. However, the stringent growth condition photovoltage limit power conversion efficiency (PCE). Herein, via a combined theoretical experimental study, interface engineering oxygenated cadmium sulfide (CdS) window layer (CdS:O) found be effective approach...
We report on the dielectric properties of BaxSr1−xTiO3 (BST) films grown by molecular beam epitaxy epitaxial Pt bottom electrodes. Paraelectric (x ≲ 0.5) exhibit losses that are similar to those BST single crystals and ceramics. Films with device quality factors greater than 1000 electric field tunabilities exceeding 1:5 demonstrated. The results provide evidence for importance stoichiometry control use a non-energetic deposition technique achieving high figures merit tunable devices thin films.
Abstract Resistive switching effects in transition metal oxide-based devices offer new opportunities for information storage and computing technologies. Although it is known that resistive a defect-driven phenomenon, the precise mechanisms are still poorly understood owing to difficulty of systematically controlling specific point defects. As result, obtaining reliable reproducible remains major challenge this technology. Here, we demonstrate control based on intentional manipulation native...
Bulk NdNiO3 exhibits a metal-to-insulator transition (MIT) as the temperature is lowered that also seen in tensile strained films. In contrast, films are under large compressive strain typically remain metallic at all temperatures. To clarify microscopic origins of this behavior, we use position averaged convergent beam electron diffraction scanning transmission microscopy to characterize both above and below MIT temperature. We show symmetry lowering structural change takes place case film,...
The Hall coefficient of epitaxial NdNiO3 films is evaluated in a wide range temperatures, from the metallic into insulating phase. It shown that for temperatures which and regions co-exist, must be corrected time-dependence longitudinal resistance, due to slow evolution domains. positive negative Seebeck coefficients, respectively, phase are characteristic two bands participating transport. change sign values consistent with suppression contribution large hole-like Fermi surface, i.e.,...
Abstract Single crystals of disordered Mn 4– x Cr Al 11 have been synthesized via the flux method. EDS on several various sizes and shapes revealed an average molar ratio 17:9:74 for Mn:Cr:Al, while X-ray diffraction three different yield compositions 2.26 1.74 (Mn , = 1.74), 0.83 3.17 1.07 2.93 . This compound crystallizes in space group P –1, isostructural with both 4 Magnetic measurements show that this is ferrimagnetic a low effective moment μ eff ≈1.012±0.004 B /f.u. non-reachable...
We report on tunneling measurements that reveal the evolution of quasiparticle state density in two rare earth perovskite nickelates, NdNiO3 and LaNiO3, are close to a bandwidth controlled metal insulator transition. measure opening sharp gap ∼30 meV its insulating ground state. which remains correlated at all practical temperatures, exhibits pseudogap same order. The results point both types gaps arising from common origin, namely, quantum critical associated with T = 0 K metal-insulator...
Using aberration-corrected high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), we investigate ordering phenomena in epitaxial thin films of the double perovskite Sr_{2}CrReO_{6}. Experimental and simulated imaging diffraction are used to identify antiphase domains films. Image simulation provides insight into effects atomic-scale along beam direction on HAADF-STEM intensity. We show that probe channeling results ±20% variation intensity for a given...
p-type Cr2MnO4 with bandgap 3.01 eV was sputter deposited onto (2¯01) and (001) n-type or semi-insulating β-Ga2O3.The heterojunction of CrMnO4 on Ga2O3 is found to be type II, staggered gap, i.e., the band offsets are such that both conduction valence edges lower in energy than those Cr2MnO4. This creates a alignment, which can facilitate separation photogenerated electron-hole pairs. The edge higher by 1.82–1.93 depending substrate orientation doping, means holes would have barrier overcome...