A5066083825- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- X-ray Diffraction in Crystallography
- Magnetic and transport properties of perovskites and related materials
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Rare-earth and actinide compounds
- Nuclear materials and radiation effects
- Crystal Structures and Properties
- Methane Hydrates and Related Phenomena
- Iron-based superconductors research
- Multiferroics and related materials
- Crystallization and Solubility Studies
- Luminescence Properties of Advanced Materials
- Solid-state spectroscopy and crystallography
- Advanced Thermoelectric Materials and Devices
- Electronic and Structural Properties of Oxides
- Ferroelectric and Piezoelectric Materials
- Inorganic Chemistry and Materials
- Inorganic Fluorides and Related Compounds
- Geological and Geochemical Analysis
- Radiation Detection and Scintillator Technologies
- Radioactive element chemistry and processing
- Atomic and Subatomic Physics Research
- Chemical Synthesis and Characterization
Oak Ridge National Laboratory
2016-2025
Quantum Science Center
2012-2019
Government of the United States of America
2019
Oak Ridge Associated Universities
2015-2018
The University of Western Australia
2011
Yamagata University
2011
Institute of Molecular Science and Technologies
2011
Hamburg Institut (Germany)
2008
Harbin Institute of Technology
2008
St Petersburg University
2008
Crystallographic data, electrical and thermal transport measurements, magnetic susceptibility values are reported for several compounds alloys with the filled skutterudite structure, ${R}_{1\ensuremath{-}y}{\mathrm{Fe}}_{4\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{Sb}}_{12}$ ($R=\mathrm{La},$ Ce, or Th; $0<y<1;$ $x=0,$1). Room-temperature velocity of sound data is also reported. These materials interest because their potential in thermoelectric power generation refrigeration...
Structural, magnetic, electrical and thermal transport, heat-capacity measurements are reported on single crystals of ${\mathrm{Eu}}_{8}{\mathrm{Ga}}_{16}{\mathrm{Ge}}_{30},$ ${\mathrm{Sr}}_{8}{\mathrm{Ga}}_{16}{\mathrm{Ge}}_{30},$ ${\mathrm{Ba}}_{8}{\mathrm{Ga}}_{16}{\mathrm{Ge}}_{30}.$ These compounds all crystallize in a cubic type-I ice clathrate structure, interest as potential thermoelectric materials. Neutron-diffraction were made crystal...
We have combined single-crystal neutron and x-ray diffractions to investigate the magnetic crystal structures of honeycomb lattice Na${}_{2}$IrO${}_{3}$. The system orders magnetically below $18.1(2)$ K with Ir${}^{4+}$ ions forming zigzag spin chains within layered network an ordered moment $0.22(1){\ensuremath{\mu}}_{\text{B}}/\text{Ir}$ site. Such a configuration sharply contrasts N\'eel or stripe states proposed in Kitaev-Heisenberg model. structure refinement reveals that Ir atoms form...
Single crystals of the Kitaev spin-liquid candidate $\alpha$-RuCl$_3$ have been studied to determine low-temperature bulk properties, structure and magnetic ground state. Refinements x-ray diffraction data show that low temperature crystal is described by space group $C2/m$ with a nearly-perfect honeycomb lattice exhibiting less than 0.2 \% in-plane distortion. The as-grown single exhibit only one sharp transition at $T_{N}$ = 7~K. order below this exhibits propagation vector $k$ (0, 1,...
The Kitaev model on a honeycomb lattice predicts paradigmatic quantum spin liquid (QSL) exhibiting Majorana Fermion excitations. insight that physics might be realized in practice has stimulated investigations of candidate materials, recently including alpha-RuCl3. In all the systems studied to date, non-Kitaev interactions induce magnetic order at low temperature. However, in-plane fields roughly 8 Tesla suppress long-range alpha-RuCl3 raising intriguing possibility field-induced QSL...
The structure of CaTiO3 has been studied at high temperatures by powder neutron diffraction methods. From inspection the data two phase transitions are evident, with an intermediate tetragonal (I/mcm) forming near 1500 K and a primitive cubic above 1580 K. Detailed Rietveld analyses suggest there may also be transition from room temperature Pbnm to orthorhombic Cmcm around 1380 A remarkable feature results is regular variation in out-of-phase octahedral tilt angle over entire range.
Crystallographic data, electrical and thermal transport measurements, heat-capacity data are reported for several compounds with the filled skutterudite structure: ${\mathrm{Tl}}_{x}{\mathrm{Co}}_{4\ensuremath{-}y}{\mathrm{Fe}}_{y}{\mathrm{Sb}}_{12}$ ${\mathrm{Tl}}_{x}{\mathrm{Co}}_{4}{\mathrm{Sb}}_{12\ensuremath{-}y}{\mathrm{Sn}}_{y},$ where $0<(x,y)<1$ $x\ensuremath{\approx}y.$ These materials have potential use thermoelectric power generation. The Tl atomic displacement parameters...
The magnetic properties of spinel nanoparticles are determined by crystal chemistry issues such as cation distribution and oxidation states. state Mn−Fe have been systematically studied at various temperatures using neutron diffraction electron energy loss spectroscopy, respectively. prepared coprecipitation a high degree inversion with 61% the tetrahedral sites occupied Fe3+ cations. correlates expected from random occupancy cations consisting Fe (60%) Mn (40%). After heat treatment in...
Neutron powder diffraction has been used to examine the structural changes of rare-earth aluminates LaAlO3 , PrAlO3and NdAlO3over a wide range temperatures. At room temperature, all three adopt rhombohedral perovskite structure in space group R c(a= 5.3647(1) Å, c= 13.1114(3) Å for a= 5.3337(2) 12.9842(4) PrAlO3 5.3223(2) 12.9292(5) NdAlO3 ). The is characterized by rotation oxygen atom octahedra about threefold axis, and compression these parallel same axis. As temperature increased, angle...
The high-temperature phase transitions of ${\mathrm{SrZrO}}_{3}$ have been studied using powder neutron diffraction and the Rietveld method. material is tetragonal $(I4/mcm)$ between \ensuremath{\sim}1020 1360 K. At higher temperatures (>1360 K) structure was found to be ideal cubic perovskite $(Pm3\ifmmode\bar\else\textasciimacron\fi{}m).$ From neutron-diffraction data space-group assignments, transition from consistent with a continuous transition. angle tilt oxygen octahedron in taken...
A mixed alkali metal titanate of composition AxTi2-x/3Lix/3O4 (A = K, Rb, Cs) has been prepared and its ion-exchange/intercalation properties have explored. Solid-state calcination appropriate mixtures TiO2 carbonates produced the at a stoichiometry x 0.80 for 0.75 0.70 Cs. Rietveld refinement on neutron diffraction data confirmed that orthorhombic structure is comprised lepidocrocite-related host layers Ti2-x/3Lix/3O4 charge-balancing ions in interlayer domain. Complete extraction both was...
A natural single crystal of zircon, ZrSiO(4,) from Sri Lanka exhibited zonation due to alpha-decay damage. The zones vary in thickness on a scale one hundreds micrometers. uranium and thorium concentrations zone such that the dose is between 0.2 x 10(16) 0.8 alpha-events per milligram (0.15 0.60 displacement atom). transition crystalline aperiodic metamict state occurs over this range. Differential expansion individual layers variations their caused systematic pattern fractures do not...
Structure I (sI) carbon dioxide (CO2) hydrate exhibits markedly different dissociation behavior from sI methane (CH4) in experiments which equilibrated samples at 0.1 MPa are heated isobarically 13 K/h 210 K through the H2O melting point (273.15 K). The CO2 release only about 3% of their gas content up to temperatures 240 K, is 22 above phase boundary. Up 20% released by 270 and remaining 271.0 ± 0.5 where sample temperature buffered until ceases. This reproducible buffering for reaction...
We report a single-crystal neutron diffraction study of the layered $\rm Sr_2IrO_4$. This work unambiguously determines magnetic structure system and reveals that spin orientation rigidly tracks staggered rotation IrO_6$ octahedra in The long-range antiferromagnetic order has canted configuration with an ordered moment 0.208(3) $μ_B$/Ir site within basal plane; detailed examination canting yields 0.202(3) 0.049(2) $μ_B$/site for axis b axis, respectively. It is intriguing forbidden nuclear...
Large enhancements in the critical current density Jc were produced single crystals of high-temperature superconductor Bi2Sr2Ca1Cu2O8 by irradiation with high energy Sn ions. In addition, irreversibility line was moved to considerably higher magnetic fields. contrast analogous studies on Y1Ba2Cu3O7, there little, if any, selective pinning when magnetizing field applied parallel linear, ion-damage-produced tracks.
Abstract Multiferroics materials, which exhibit coupled magnetic and ferroelectric properties, have attracted tremendous research interest because of their potential in constructing next-generation multifunctional devices. The application single-phase multiferroics is currently limited by usually small magnetoelectric effects. Here, we report the realization giant effects a Y-type hexaferrite Ba 0.4 Sr 1.6 Mg 2 Fe 12 O 22 single crystal, exhibits record-breaking direct converse coefficients...
The zero-dimensional all-inorganic perovskites are self-activated blue emitters with slight hygroscopicity, scalable synthesis, and high radiation detection efficiency.
Abstract Polar van der Waals chalcogenophosphates exhibit unique properties, such as negative electrostriction and multi-well ferrielectricity, enable combining dielectric 2D electronic materials. Using low temperature piezoresponse force microscopy, we revealed coexistence of piezoelectric non-piezoelectric phases in CuInP 2 Se 6 , forming unusual domain walls with enhanced response. From systematic imaging experiments have inferred the formation a partially polarized antiferroelectric...