A5029894075- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Multiferroics and related materials
- 2D Materials and Applications
- Catalysis and Oxidation Reactions
- Nuclear materials and radiation effects
- Inorganic Chemistry and Materials
- Rare-earth and actinide compounds
- Iron-based superconductors research
- Graphene research and applications
- Topological Materials and Phenomena
- Advancements in Solid Oxide Fuel Cells
- Expert finding and Q&A systems
- Ion-surface interactions and analysis
- Advanced ceramic materials synthesis
- Superconducting Materials and Applications
- Quantum Dots Synthesis And Properties
- Metal-Catalyzed Oxygenation Mechanisms
- Perovskite Materials and Applications
- Electronic and Structural Properties of Oxides
- Quantum, superfluid, helium dynamics
- Geological and Geochemical Analysis
McMaster University
2022-2025
University of Tennessee at Knoxville
2017-2024
Brockhouse Institute for Materials Research
2022-2024
State Key Laboratory of Modern Optical Instruments
2022
Zhejiang University
2022
Beihang University
1997
National Laboratory of Solid State Microstructures
1994
The magnetic structures and spin dynamics of Na$_{2}$Co$_{2}$TeO$_{6}$ Na$_{2}$Ni$_{2}$TeO$_{6}$ are investigated by means elastic inelastic neutron scattering measurements the results discussed in context a generalized Kitaev-Heisenberg model on honeycomb lattice with strong spin-orbit coupling. large number parameters involved Hamiltonian evaluated using an iterative optimization algorithm capable extracting solutions simultaneously estimating their uncertainty. analyses establish that...
The discovery of atomically thin van der Waals magnets (e.g., CrI3 and Cr2Ge2Te6) has triggered a renaissance in the study two-dimensional (2D) magnetism. Most 2D magnetic compounds discovered so far host only one single phase unless system is at boundary. In this work, we report near degeneracy phases ultrathin chromium telluride (Cr2Te3) layers with strong perpendicular anisotropy highly desired for stabilizing order. Single-crystalline Cr2Te3 nanoplates trigonal structure (space group...
The phase diagram of the kagome metal family $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ ($A=\mathrm{K}$, Rb, Cs) features both superconductivity and charge density wave (CDW) instabilities, which have generated tremendous recent attention. Nonetheless, significant questions remain. In particular, temperature evolution demise CDW state has not been extensively studied, little is known about coexistence with at low temperatures. We report an x-ray scattering study...
Molecular orbital systems with clusters of heavy transition metal (TM) ions are one the most important classes model materials for studying interplay between local physics and effects itinerancy. Despite a large number candidates identified in family $4d\text{ }\mathrm{TM}$ materials, an understanding their from competing microscopic energy scales is still missing. We bridge this gap by reporting first resonant inelastic x-ray scattering (RIXS) measurement on well-known series Ru cluster...
Kitaev materials, based on bond-directional Ising interactions, offer an intriguing platform for hosting exotic magnetic ground states and excitations. Significant interactions are most commonly realized in heavy transition metal magnets with so-called ${J}_{\mathrm{eff}}$ = \textonehalf{} electronic the local geometries consisting of metal-ligand edge-sharing octahedra. Here, authors show that materials can also be via extended superexchange pathways mediated by more than one anion.
We have performed magnetic susceptibility, heat capacity, muon spin relaxation, and neutron-scattering measurements on three members of the family ${\mathrm{Ba}}_{3}M{\mathrm{Ru}}_{2}{\mathrm{O}}_{9}$, where $M\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}\mathrm{In}$, Y, Lu. These systems consist mixed-valence Ru dimers a triangular lattice with antiferromagnetic interdimer exchange. Although previous work has argued that charge order within or intradimer double exchange plays an...
We systematically investigate the magnetic properties and local structure of ${\mathrm{Ba}}_{2}{\mathrm{YIrO}}_{6}$ to demonstrate that Y Ir lattice defects in form antiphase boundary or clusters antisite disorder affect magnetism observed this $5{d}^{4}$ compound. The experimental investigation involved comparison atomic imaging (1) a slow-cooled crystal, (2) crystal quenched from $900{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ after growth, (3) grown using faster cooling...
Heavy transition metal magnets with $J_{\rm eff}$ $=$ 1/2 electronic ground states have attracted recent interest due to their penchant for hosting new classes of quantum spin liquids and superconductors. Unfortunately, model systems ideal are scarce the importance non-cubic local distortions in most candidate materials. In this work, we identify a family iridium halide [i.e. K$_2$IrCl$_6$, K$_2$IrBr$_6$, (NH$_4$)$_2$IrCl$_6$, Na$_2$IrCl$_6 \cdotp $ 6(H$_2$O)] Ir$^{4+}$ extremely close...
Magnetic excitations in the spin chain candidate ${\mathrm{Sr}}_{2}{\mathrm{V}}_{3}{\mathrm{O}}_{9}$ have been investigated by inelastic neutron scattering on a single crystal sample. A spinon continuum with bandwidth of $\ensuremath{\sim}22$ meV is observed along formed alternating magnetic ${\mathrm{V}}^{4+}$ and nonmagnetic ${\mathrm{V}}^{5+}$ ions, which reveals importance orbital degree freedom determining axis as identified prior electronic structure calculations. Incipient Bragg peaks...
The topological phases and their dependence on the lattice constant in zirconium pentatelluride ZrTe${}_{5}$ have been under heated debate. Here, authors study temperature evolution of Dirac band find no indication band-gap closure as changes. They show that a weak insulator phase across range may not be only explanation. A transition is still possible if mixing inversion are considered.
The experimentally observed softening of the oxygen breathing mode at X point, ${\mathrm{O}}_{\mathrm{X}}^{\mathrm{B}}$, and a second CuO bond stretching ${\mathrm{\ensuremath{\Delta}}}_{1}$ symmetry wave vector q=(0.5,0,0) in doped metallic phase La-Cu-O is investigated shown to be driven by long-range, nonlocal electron-phonon interaction effects monopole charge-redistribution type. amplification for both modes about 1 THz, recently found inelastic neutron scattering an optimally...
Transition metal oxides of the $4d$ and $5d$ block have recently become targets materials discovery, largely due to their strong spin-orbit coupling that can generate exotic magnetic electronic states. Here we report high pressure synthesis Lu$_2$Rh$_2$O$_7$, a new cubic pyrochlore oxide based on $4d^5$ Rh$^{4+}$ characterizations via thermodynamic, electrical transport, muon spin relaxation measurements. Magnetic susceptibility measurements reveal large temperature-independent Pauli...
Iridates with the $5{d}^{4}$ electronic configuration have attracted recent interest due to reports of magnetically ordered ground states despite longstanding expectations that their strong spin-orbit coupling would generate a $J=0$ state for each ${\mathrm{Ir}}^{5+}$ ion. The major focus prior research has been on double perovskite iridates ${\mathrm{Ba}}_{2}{\mathrm{YIrO}}_{6}$ and ${\mathrm{Sr}}_{2}{\mathrm{YIrO}}_{6}$, where nature (i.e., vs nonmagnetic) is still controversial. Here, we...
We present the synthesis and magnetic characterization of a polycrystalline sample 6H-perovskite Ba3CeRu2O9, which consists Ru dimers based on face-sharing RuO6 octahedra. Our low-temperature susceptibility, magnetization, neutron powder diffraction results reveal nonmagnetic singlet ground state for dimers. Inelastic scattering, infrared spectroscopy, susceptibility over wide temperature range are best explained by molecular orbital model with zero-field splitting parameter D = 85 meV Stot...
Molecular magnets based on heavy transition metals have recently attracted significant interest in the quest for novel magnetic properties. For systems with an odd number of valence electrons per molecule, high or low molecular spin states are typically expected double exchange quasimolecular orbital limits, respectively. In this work, we use bulk characterization, muon relaxation, neutron diffraction, and inelastic scattering to identify a rare intermediate spin-3/2 dimer state...
FePt5P, a substitutional variant of the anti-CeCoIn5 structure type in space group P4/mmm, was synthesized by high-temperature solid-state method and structurally characterized X-ray diffraction. FePt5P contains layers FePt12 clusters formed magnetically active Fe heavy Pt with strong spin-orbit coupling (SOC); are separated P atoms. The various Fe–Pt distances generate complex magnetic orders FePt5P. According to temperature-dependent specific heat measurements, shows stripe-type...
We present the synthesis and physical properties of a breathing pyrochlore magnet ${\mathrm{CuAlCr}}_{4}{\mathrm{S}}_{8}$ via synchrotron x-ray diffraction, magnetization under ambient applied hydrostatic pressure, heat capacity, muon spin relaxation/rotation measurements. exhibits positive thermal expansion with concave upward temperature dependence. observed sharp antiferromagnetic ordering transition purely magnetic nature at 20 K, which shifts by as much 3.2 K on application 600 MPa...
The metal-metal bond in metal-rich chalcogenide is known to exhibit various structures and dominate interesting physical properties. Ta2Se can be obtained by both arc-melting solid-state pellet methods. crystallizes a layered tetragonal structure with space group P4/nmm (S.G.129, Pearson symbol tP6). Each unit cell consists of four layers body-centered closed packing Ta atoms sandwiched between two square nets Se atoms, forming the Se-Ta-Ta-Ta-Ta-Se networks. A combined result magnetic...
Iridates with the 5$d^4$ electronic configuration have attracted recent interest due to reports of magnetically-ordered ground states despite longstanding expectations that their strong spin-orbit coupling would generate a $J = 0$ state for each Ir$^{5+}$ ion. The major focus prior research has been on double perovskite iridates Ba$_2$YIrO$_6$ and Sr$_2$YIrO$_6$, where nature (i.e. ordered vs non-magnetic) is still controversial. Here we present neutron powder diffraction, high energy...
Molecular magnets with one unpaired electron per molecule offer promise in the ongoing search for exotic states of matter, including quantum spin liquids. Here, authors investigate a series molecular based on Mo trimer building blocks each and find that magnetic ground are very sensitive to small changes breathing parameter---the ratio between first second nearest neighbor bond lengths kagome lattice they form. When this parameter is sufficiently close 1, these materials show an absence...
We report a thorough study of Y$_{0.7}$La$_{0.3}$VO$_3$ single crystals by measuring magnetic properties, specific heat, thermal conductivity, x-ray and neutron diffraction with the motivation revealing lattice response to spin-orbital entanglement in \textit{R}VO$_3$. Upon cooling from room temperature, orbitally disordered paramagnetic state changes around T*$\sim$220\,K entangled which is then followed transition at T$_N$=116\,K C-type orbital ordered (OO) G-type antiferromagnetic (AF)...