A5030811418- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Iron-based superconductors research
- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Crystallography and molecular interactions
- Superconductivity in MgB2 and Alloys
- Magnetic and transport properties of perovskites and related materials
- Corporate Taxation and Avoidance
- Topological Materials and Phenomena
- Ferroelectric and Piezoelectric Materials
- Advanced X-ray Imaging Techniques
- Inorganic Chemistry and Materials
- Crystallography and Radiation Phenomena
- Multiferroics and related materials
- Diamond and Carbon-based Materials Research
- Force Microscopy Techniques and Applications
- 2D Materials and Applications
- Intellectual Capital and Performance Analysis
- Quantum Dots Synthesis And Properties
- High-pressure geophysics and materials
- Nuclear materials and radiation effects
- Magnetism in coordination complexes
- Metal-Organic Frameworks: Synthesis and Applications
École Polytechnique Fédérale de Lausanne
2020-2024
Ames National Laboratory
2012-2023
Iowa State University
2020-2022
We study the relationship between precipitate morphology and superconductivity in KxFe1.6+ySe2 single crystals grown by self-flux method. Scanning electron microscopy (SEM) measurements revealed that superconducting phase forms a network samples quenched above iron vacancy order-disorder transition temperature Ts. For obtained natural cooling down to room furnace, referred as furnace cooling, aggregates into micrometer-sized rectangular bars aligns disconnected chains. Accompanying this...
Large high-quality single crystals of hole-doped iron-based superconductor (Ba${}_{1\ensuremath{-}x}$K${}_{x}$)Fe${}_{2}$As${}_{2}$ were grown over a broad composition range $0.22\ensuremath{\le}x\ensuremath{\le}1$ by inverted temperature gradient method. We found that high soaking temperature, fast cooling rate, and an adjusted window the growth are necessary to obtain heavily K-doped ($0.65\ensuremath{\le}x\ensuremath{\le}0.92$) with narrow compositional distributions as revealed sharp...
Abstract We report the growth of high-quality single crystals hole-doped composition <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>Sr</mml:mi> </mml:mrow> <mml:mn>0.95</mml:mn> </mml:msub> <mml:mi mathvariant="normal">K</mml:mi> <mml:mn>0.05</mml:mn> <mml:mi>Co</mml:mi> <mml:mn>2</mml:mn> <mml:mi>As</mml:mi> </mml:math> and present an investigation its structural, electronic, thermal, magnetic properties. Our results show that hole...
${\mathrm{EuMnSb}}_{2}$ is a candidate topological material which can be tuned towards Weyl semimetal, but there are differing reports for its antiferromagnetic (AFM) phases. The coupling of bands dominated by pure Sb layers hosting fermions to Mn and Eu magnetic states provides potential path tune the properties. Here we present single-crystal neutron diffraction, magnetization, heat-capacity data as well polycrystalline $^{151}\mathrm{Eu}$ M\"ossbauer show that three AFM phases exist...
Non-invasive magnetic field sensing using optically - detected resonance of nitrogen-vacancy (NV) centers in diamond was used to study spatial distribution the induction upon penetration and expulsion weak fields several representative superconductors. Vector were measured on surface conventional, Pb Nb, unconventional, LuNi$_2$B$_2$C, Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$, Ba(Fe$_{0.93}$Co$_{0.07}$)$_2$As$_2$, CaKFe$_4$As$_4$, superconductors, with diffraction limited resolution variable...
We report the growth of YTiO3 single crystals using different starting materials with nominal compositions, (1) stoichiometric YTiO3; (2) oxygen deficient YTiO2.925; (3) YTiO2.85, and atmospheres, 97%Ar/ 3%H2; Ar; forming gas 95%N2/ 5%H2, laser floating zone technique. The oxygen-deficient were prepared by mixing Y2O3, Ti2O3, Ti powder according to YTiO3-δ stoichiometry. addition effectively reacts in furnace chamber, reducing Ti4+ ion-containing impurities. High-quality (2 0 0) facet grown...
Neutron diffraction, magnetization, and muon spin relaxation measurements, supplemented by density functional theory (DFT) calculations are employed to unravel temperature-driven magnetization reversal in inverse spinel ${\mathrm{Co}}_{2}{\mathrm{VO}}_{4}$. All measurements show a second-order magnetic phase transition at ${T}_{\mathrm{C}}=168\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ collinear ferrimagnetic phase. diffraction reveal two antiparallel ferromagnetic (FM) sublattices, belonging...
Neutron diffraction and magnetic susceptibility studies show that orthorhombic single-crystals of topological semimetals $\mathrm{Sr}({\mathrm{Mn}}_{0.9}{\mathrm{Cu}}_{0.1}){\mathrm{Sb}}_{2}$ $\mathrm{Sr}({\mathrm{Mn}}_{0.9}{\mathrm{Zn}}_{0.1}){\mathrm{Sb}}_{2}$ undergo three-dimensional C-type antiferromagnetic (AFM) ordering the ${\mathrm{Mn}}^{2+}$ moments at ${T}_{N}=200\ifmmode\pm\else\textpm\fi{}10$ $210\ifmmode\pm\else\textpm\fi{}12$ K, respectively, significantly lower than parent...
Low-temperature variable-energy electron irradiation was used to induce non-magnetic disorder in a single crystal of hole-doped iron-based superconductor, Ba$_{1-x}$K$_x$Fe$_2$As$_2$, $x=$0.80. To avoid systematic errors, the beam energy adjusted non-consequently for five values between 1.0 and 2.5 MeV, whence sample resistance measured in-situ at 22 K. For all energies, resistivity raises linearly with fluence suggesting creation uncorrelated dilute point-like (confirmed by simulations)....
The resonant scattering and diffraction beamline P09 at PETRA III DESY is equipped with a 14 T vertical field split-pair magnet. A helium-3 refrigerator available that can be fitted inside the magnet's variable-temperature insert. Here results of series experiments aimed determining beam conditions permitting operations He-3 insert are presented. By measuring tetragonal-to-orthorhombic phase transition occurring 2.1 K in Jahn-Teller compound TmVO4, it found photon flux must attenuated down...
High-quality single crystals of ${\mathrm{KCo}}_{2}{\mathrm{As}}_{2}$ with the body-centered tetragonal ${\mathrm{ThCr}}_{2}{\mathrm{Si}}_{2}$ structure were grown using KAs self flux. Structural, magnetic, thermal, and electrical transport properties investigated. No clear evidence for any phase transitions was found in temperature range 2--300 K. The in-plane resistivity $\ensuremath{\rho}$ versus $T$ is highly unusual, showing a ${T}^{4}$ behavior below 30 K an anomalous positive...
Dark blue single crystals of Al1.753+Ti1.04+Ti0.253+O5 were grown with a novel synthesis method based on the reaction Ti3+/Ti4+-containing langbeinite melt and porous α-alumina crucible. The obtained needles crystallize in pseudobrookite structure and, upon heating, undergo two reversible phase transitions, from orthorhombic Cmcm to C2/m first subsequently C2 symmetry. Like known aluminum titanate pseudobrookites, anisotropic thermal expansion is observed. temperature evolution crystal...
This study introduces bis-[hexa-kis-(nitrato-κ
Crystal growth is inherently multidisciplinary, encompassing fields such as thermodynamics and kinetics, fluid dynamics, solution solid-state chemistry, process engineering, defects engineering to name a few [...]
Uniaxial stress is used to detwin the samples of orthorhombic iron based superconductors study their intrinsic electronic anisotropy. Here, we describe development a new detwinning setup enabling variable-load stress-detwinning with easy sample mounting/dismounting without need re-solder contacts. It enables systematic anisotropy evolution as function an external parameter when modified between measurements. In our case, dose 2.5 MeV electron irradiation at low temperature. We illustrate...
In-plane anisotropy of electrical resistivity was studied in samples the hole-doped ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ composition range $0.21\ensuremath{\le}x\ensuremath{\le}0.26$ where changes sign. Low-temperature ($\ensuremath{\sim}20$ K) irradiation with relativistic 2.5 MeV electrons used to control level disorder and residual samples. Modification stress-detwinning technique enabled measurements same before after irradiation, leading...