A5043085937- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Rare-earth and actinide compounds
- Multiferroics and related materials
- Magnetic Properties of Alloys
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Crystal Structures and Properties
- Inorganic Chemistry and Materials
- High-pressure geophysics and materials
- Electronic and Structural Properties of Oxides
- X-ray Diffraction in Crystallography
- Ferroelectric and Piezoelectric Materials
- Advancements in Solid Oxide Fuel Cells
- Thermal Expansion and Ionic Conductivity
- Crystallization and Solubility Studies
- Nuclear materials and radiation effects
- MXene and MAX Phase Materials
- Solid-state spectroscopy and crystallography
- Inorganic Fluorides and Related Compounds
- Magnetic properties of thin films
- Theoretical and Computational Physics
- Advanced Thermoelectric Materials and Devices
- Magnetic Properties and Synthesis of Ferrites
- Shape Memory Alloy Transformations
Institut Laue-Langevin
2016-2025
Uganda Martyrs University
2025
Institut Langevin
2012-2024
Robert Bosch (Germany)
2021
Max Planck Institute for Solid State Research
2020
Brock University
2019
Bhabha Atomic Research Centre
2017
National Research University of Electronic Technology
2017
University of Aberdeen
2017
Kyoto University
2008-2016
A systematic study of the effect oxygen content on structural, magnetotransport, and magnetic properties has been undertaken a series ${\mathrm{LaMnO}}_{3+\mathrm{\ensuremath{\delta}}}$ samples, with $\ensuremath{\delta}=0,$ 0.025, 0.07, 0.1, 0.15. Measurements ac initial susceptibility, magnetization, magnetoresistance, neutron diffraction, including small-angle scattering (SANS), were performed in temperature range 1--320 K using high fields up to 12 T. The antiferromagnetic order found...
The effects of magnetic field and pressure on the unusual spontaneous behavior ${\mathrm{La}}_{2/3}$${\mathrm{Ca}}_{1/3}$${\mathrm{MnO}}_{3}$ have been thoroughly investigated. Resistivity volume thermal expansion, both under pressure, ac susceptibility magnetostriction, magnetoresistance, neutron diffraction measurements, allowed us to determine relevant underlying mechanisms in this system. Above ${\mathit{T}}_{\mathit{c}}$ measurements reveal short-range ferromagnetic correlations...
A thorough study of the low-temperature magnetic state polycrystalline $({\mathrm{Tb}}_{1/3}{\mathrm{La}}_{2/3}{)}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ has been carried out. This perovskitelike compound is an insulator at low temperatures and shows insulator-metal transition under field. All measurements its (magnetization, susceptibility, neutron diffraction) are consistent with spin-glass behavior. The electronic phase diagram for series...
Room temperature x-ray diffraction, magnetization and neutron diffraction measurements up to 500 K have been carried out on polycrystalline bulk double perovskites AA'FeMoO6 (AA' = Ba2, BaSr, Sr2, Ca2) in order determine correlate their structural magnetic properties. As the average ionic radius is diminished, crystallographic structure evolves from cubic (for AA' BaSr) tetragonal (Sr2) finally monoclinic (Ca2). In case of a novel crossover high paramagnetic state low ferrimagnetic has...
The effect of the substitution for Mn with Al in magnetoresistive perovskite ${\mathrm{La}}_{2\mathrm{/}3}$${\mathrm{Ca}}_{1\mathrm{/}3}$${\mathrm{MnO}}_{3}$ has been studied by preparing series ${\mathrm{La}}_{2\mathrm{/}3}$${\mathrm{Ca}}_{1\mathrm{/}3}$${\mathrm{Mn}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Al}}_{\mathrm{x}}$${\mathrm{O}}_{3}$ (x\ensuremath{\leqslant}0.2). A careful study magnetic, structural, and transport properties carried out means electrical resistance,...
The onset of a Griffiths-like phase has been observed in Tb5Si2Ge2 (TC=110 K) by means magnetic susceptibility and small-angle neutron scattering experiments. We show the growth ferromagnetic cluster system characterized an inverse exponent lower than unity at TC<T<TG approximately 200 K. suggest that state is originated local disorder within crystallographic structure, stabilized enhanced competing intralayer interlayer interactions. Both factors thus promote segregation nanometric regions with
The crystal and magnetic structures of orthorhombic ε-Fe2O3 have been studied by simultaneous Rietveld refinement X-ray neutron powder-diffraction data in combination with Mössbauer spectroscopy, as well magnetization heat-capacity measurements. It has found that above 150 K, the polymorph is a collinear ferrimagnet moments directed along axis, whereas ordering below 80 K characterized square-wave incommensurate structure. transformation between these two states second-order phase transition...
Variable temperature neutron diffraction was carried out on mesoporous α-Fe2O3 (hematite) with a mean pore diameter of 38.5 Å. Data were directly compared to measurements bulk hematite. Unlike hematite, the material does not undergo spin−flop transition from weak ferromagnet pure antiferromagnet (Morin transition, TM = 259.1(2)). Instead, remains down 2 K magnetic moments staying perpendicular R3̅c [111] ([003] in hexagonal cell) direction rather than realigning (to) almost parallel this...
The low temperature state of CeRu2Al10 has been studied by neutron powder diffraction and muon spin relaxation (muSR). By combining both techniques, we prove that the transition occurring below T*~27K, which subject considerable debate, is unambiguously magnetic due to ordering Ce sublattice. structure with propagation vector k=(1,0,0) involves collinear antiferromagnetic alignment moments along c-axis Cmcm space group a reduced moment 0.34(2)mu_B. No structural changes within resolution...
The nuclear and magnetic structures of ${\text{Fe}}_{1+y}{\text{Te}}_{1\ensuremath{-}x}{\text{Se}}_{x}$ $(0\ensuremath{\le}x\ensuremath{\le}0.20)$ compounds was analyzed between 2 300 K by means Rietveld refinement neutron powder diffraction data. Samples with $x\ensuremath{\le}0.075$ undergo a tetragonal to monoclinic phase transition at low temperature, whose critical temperature decreases increasing Se content; this structural is strictly coupled long-range antiferromagnetic ordering the...
In 2017, we discovered quaternary i-MAX phases—atomically layered solids, where M is an early transition metal, A group element, and X C—with a (M12/3M21/3)2AC chemistry, the M1 M2 atoms are in-plane ordered. Herein, report discovery of class magnetic phases in which bilayers quasi-2D frustrated triangular lattice overlay Mo honeycomb arrangement Al Kagomé lattice. The chemistry this family (Mo2/3RE1/3)2AlC, rare-earth, RE, elements Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu. properties were...
The crystal structure, magnetic ground state, and the temperature-dependent microscopic spin-spin correlations of frustrated honeycomb lattice antiferromagnet $\mathrm{N}{\mathrm{a}}_{2}\mathrm{C}{\mathrm{o}}_{2}\mathrm{Te}{\mathrm{O}}_{6}$ have been investigated by powder neutron diffraction. A long-range antiferromagnetic (AFM) ordering has found below ${T}_{\mathrm{N}}\ensuremath{\sim}24.8\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. determined to be zigzag characterized a propagation vector...
The crystal and magnetic structures of ${\mathrm{Tb}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ series have been studied by x-ray neutron-diffraction techniques. Macroscopic properties characterized using ac susceptibility measurements. relationships between structural behaviors are discussed. Our study shows that the magnetism manganese in this system is very complex due to small size rare earth. ${\mathrm{TbMnO}}_{3}$ does not develop a simple A-type order, as...
Using neutron diffraction, 170Yb Mössbauer and muon spin relaxation spectroscopies, we have examined the pyrochlore Yb2Ti2O7, where Yb3+S' = 1/2 ground state has planar anisotropy. Below approximately 0.24 K, temperature of known specific-heat lambda transition, there is no long range magnetic order. We show that transition corresponds to a first-order change in fluctuation rate Yb3+ spins. Above temperature, rate, GHz range, follows thermal excitation law, whereas below, MHz independent,...
Jarosites are a family of minerals general formula ${\mathrm{AFe}}_{3}{(\mathrm{OH})}_{6}{(\mathrm{S}\mathrm{O}}_{4}{)}_{2}$ (where ${A}^{+}$ is typically univalent cation such as ${\mathrm{Na}}^{+},$ ${\mathrm{K}}^{+},$ ${\mathrm{Rb}}^{+},$ ${\mathrm{ND}}_{4}^{+},$ ${\mathrm{Ag}}^{+},$ ${\mathrm{Tl}}^{+},$ or ${\mathrm{D}}_{3}{\mathrm{O}}^{+}).$ They provide good model Heisenberg kagom\'e antiferromagnets with which to test suggestions that highly frustrated have unconventional magnetic...
Magnetization, heat capacity, and neutron diffraction experiments on the \ensuremath{\beta}-phase of dithiadiazolyl radical, p-NC.${\mathrm{C}}_{6}$${\mathrm{F}}_{4}$.CNSSN., provide conclusive evidence that this system exhibits noncollinear antiferromagnetism at 35.5 K, an unprecedented temperature for organic radical. On basis magnetization powder results, coupled with theoretical calculations spin distribution within molecule, a magnetic structure compound is proposed in which...
Effects of temperature and pressure on magnetic, elastic, structural, thermal properties Tb5Si2Ge2 have been studied by means macroscopic (thermal expansion magnetization) microscopic (neutron powder diffraction) techniques. We present evidence that the high-temperature second-order ferromagnetic transition can be coupled with low-temperature first-order structural phase change into a single magnetic-crystallographic transformation at above tricritical point in vicinity 8.6 kbar. This...
We report a spectacularly high orbital/charge ordering temperature ${T}_{\mathrm{CO}}=475\mathrm{K},$ in ${\mathrm{Bi}}_{1/2}{\mathrm{Sr}}_{1/2}{\mathrm{MnO}}_{3}.$ The charges order approximately $350\mathrm{K}$ above the predicted by bandwidth tuning mechanism ${\mathrm{Ln}}_{1/2}(\mathrm{C}\mathrm{a},\mathrm{S}\mathrm{r}{)}_{1/2}{\mathrm{MnO}}_{3}$ family. This transition takes place $150\mathrm{K}$ that ${\mathrm{Bi}}_{1/2}{\mathrm{Ca}}_{1/2}{\mathrm{MnO}}_{3}$ which is much more...