A5080271341- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Rare-earth and actinide compounds
- Nuclear materials and radiation effects
- Magnetic and transport properties of perovskites and related materials
- X-ray Diffraction in Crystallography
- Multiferroics and related materials
- Thermodynamic and Structural Properties of Metals and Alloys
- Thermal Expansion and Ionic Conductivity
- Iron-based superconductors research
- Inorganic Chemistry and Materials
- High-pressure geophysics and materials
- Crystallization and Solubility Studies
- Theoretical and Computational Physics
- Advancements in Solid Oxide Fuel Cells
- Boron and Carbon Nanomaterials Research
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Magnetism in coordination complexes
- Lanthanide and Transition Metal Complexes
- Crystal Structures and Properties
- Solid-state spectroscopy and crystallography
- Electronic and Structural Properties of Oxides
- Atomic and Subatomic Physics Research
- Copper-based nanomaterials and applications
University of Córdoba
2016-2023
Centre for Human Drug Research
2023
University of Castilla-La Mancha
2010-2017
Johns Hopkins University
2004-2017
University of Baltimore
2017
Rutherford Appleton Laboratory
2004-2017
University of Applied Sciences Utrecht
2017
Instituto Tecnológico y de Energías Renovables
2015
Hospital General Universitario de Albacete
2015
Forschungszentrum Jülich
2011
Strongly frustrated magnetism of the metallic pyrochlore oxide ${\mathrm{Pr}}_{2}{\mathrm{Ir}}_{2}{\mathrm{O}}_{7}$ has been revealed by single crystal study. While Pr $4f$ moments have an antiferromagnetic RKKY interaction energy scale $|{T}^{*}|=20\text{ }\text{ }\mathrm{K}$ mediated Ir $5d$-conduction electrons, no magnetic long-range order is found except for partial spin freezing at 120 mK. Instead, Kondo effect, including a $\mathrm{ln}T$ dependence in resistivity, emerges and leads to...
The HORACE suite of programs has been developed to work with large multiple-measurement data sets collected from time-of-flight neutron spectrometers equipped arrays position-sensitive detectors. software allows exploratory studies the four dimensions reciprocal space and excitation energy be undertaken, enabling multi-dimensional subsets visualized, algebraically manipulated, models for scattering simulated or fitted data. is designed an extensible framework, thus allowing user-customized...
A novel synthesis of the title compound, C2S3N3 (1) is reported. X- and K-band EPR spectra on dilute solutions 1 indicate delocalisation unpaired spin density over both heterocyclic rings in agreement with DFT calculations. An XRPD study indicates that it crystallises two morphologies phases formed during vacuum sublimation. The studies cooling below 230 K, only triclinic phase (P) becomes detectable, whereas warming above 320 just monoclinic (P21/c) observed. crystal structure has been...
We measured zirconium tungstate's elastic constants ${C}_{ij}$. This compound shows relatively soft, nearly isotropic with normal Poisson ratios and no approach to Born instability. ${\mathrm{Z}\mathrm{r}\mathrm{W}}_{2}{\mathrm{O}}_{8}$ ambient-temperature ${C}_{ij}$, but remarkable $d{C}_{ij}/dT$ that show dominant low-frequency acoustic-vibration modes. From the bulk modulus, we estimated total thermodynamic Gr\"uneisen parameter as $\ensuremath{\gamma}=\ensuremath{-}1.2$. The $dB/dT$...
Spin fluctuations are reported near the magnetic field driven quantum critical point in YbRh2Si2. On cooling, ferromagnetic evolve into incommensurate correlations located at q0=+/- (delta,delta) with delta=0.14 +/- 0.04 r.l.u. At low temperatures, an plane induces a sharp intra doublet resonant excitation energy E0=g muB mu0 H g=3.8 0.2. The intensity is localized zone center indicating precession of spin density extending xi=6 2 A beyond 4f site.
The elastic tensor of monocrystalline ${\mathrm{ZrW}}_{2}{\mathrm{O}}_{8}$ was determined near $300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ as a function pressure, using pulse-echo ultrasound in large-volume moissanite anvil cell. An unusual decrease bulk modulus with increased pressure observed. A framework-solid-based nonlinear model many degrees freedom predicts the observed behavior. We also observe that ${\mathrm{ReO}}_{3}$, similar framework solid but lacking necessary freedom, fails to...
Single crystal X-ray diffraction measurements have been carried out on Cd_2Re_2O_7 near and below the phase transition it exhibits at Tc' ~195 K. was recently discovered as first, to date only, superconductor with cubic pyrochlore structure. Superlattice Bragg peaks show an apparently continuous structural Tc', however order parameter displays anomalously slow growth ~Tc'/10, resolution limited critical-like scattering is seen above Tc'. High high temperature split entering low phase,...
We present a study of Y2–xZnxRu2O7 pyrochlores as function the Zn doping level x. X-ray diffraction measurements show that single-phase samples could be obtained for x < 0.2. Within allowed range x, dc conductivity revealed sizable decrease in resistivity at all investigated temperatures doped with respect to undoped ones. Neutron data = 0.2 sample showed replacing Y3+ by Zn2+ does not result formation oxygen vacancies. photoemission spectroscopy part Ru ions are 5+ oxidation state balance,...
We report on inelastic neutron-scattering (INS) measurements the molecular spin ring ${\text{CsFe}}_{8}$, in which eight spin-5/2 Fe(III) ions are coupled by nearest-neighbor antiferromagnetic Heisenberg interaction. have recorded INS data a nondeuterated powder sample up to high energies at time-of-flight spectrometers FOCUS PSI and MARI ISIS, clearly show excitation of waves ring. Due small number sites, spin-wave dispersion relation is not continuous but quantized. Furthermore, system...
The ordered magnetic structures of the title compounds have been determined from powder neutron diffraction measurements on ${}^{11}\mathrm{B}$-enriched samples down to 4 K. lowest temperature $R=\mathrm{Tb},$ Dy, and Ho all a (0 0 1/2) propagation vector. ${\mathrm{TbB}}_{2}{\mathrm{C}}_{2}$ is antiferromagnetic, but ${\mathrm{DyB}}_{2}{\mathrm{C}}_{2}$ ${\mathrm{HoB}}_{2}{\mathrm{C}}_{2}$ net ferromagnetic moment resulting four noncollinear sublattices that are consistent with either two...
The mean-square atomic displacement in hcp-phase solid $^{4}\mathrm{He}$ has been measured crystals with a molar volume of $21.3\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{3}$. It is temperature independent from $1\phantom{\rule{0.3em}{0ex}}\mathrm{K}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}140\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$, no evidence for an anomaly the vicinity proposed supersolid transition. different in-plane motions...
Abstract Ag has been shown to be a good metal for SOFC anode cermets using CO fuel. Here we have expanded on the work reported by testing Ag‐YSZ against different hydrocarbon based fuel (H 2 and CH 4 ). This study shows that while is current collector, it alone does not required catalytic activity direct oxidation of fuels needed used in anodes. As such an additional material (e.g. CeO ) needs present when other then CO.
Powder neutron diffraction studies show that boron and carbon atoms alternate in the planar pi-conjugated layers CeB(2)C(2) its lanthanide analogues, rather than being paired as was previously reported. Long short B-C bonds correspond to idealized arrangement of single double shown picture.
Spin correlations in the pyrochlore antiferromagnet Y_2Ru_2O_7 with Curie-Weiss temperature $\Theta_{CW}=-1100$ K and critical T_N=77 were examined through neutron scattering. For $T_N<T<\Theta_{CW}/3$ data show spin relaxation a rate $\hbar\Gamma= 1.17(9)k_BT$. T<T_N spectral weight moves to higher energies substantial changes up $4\times k_BT_N$. T<<T_N there is $\Delta=11(1)$ meV energy gap pronounced maximum at 19.7 meV. Throughout range wave vector dependence of inelastic scattering...
We report that Bi doping drives Pr$_x$Bi$_{2-x}$Ru$_2$O$_7$ from an antiferromagnetic insulator ($x=2$) to a metallic paramagnet ($x\approx 1$) with broad low $T$ maximum in $C/T$. Neutron scattering reveals local energy spin excitations ($\hbar\omega\approx 1$ meV) spectrum is unaffected by heating $k_BT>>\hbar\omega$. show continuous distribution of splittings the non-Kramers Pr$^{3+}$ ground state doublet such as might result various types lattice strain can account for all data.
The complex structure and magnetism of Pr$_{2-x}$Bi$_x$Ru$_2$O$_7$ was investigated by neutron scattering EXAFS. Pr has an approximate doublet ground-state the first excited state is a singlet. This overall crystal field level scheme similar to metallic Pr$_2$Ir$_2$O$_7$, which also reported here. While B-site (Ru) well ordered throughout, this not case for A-site (Pr/Bi). A distribution Pr-O2 bond length indicates environment uniform even $x=0$. Bi highly disordered ostensibly due 6s lone...
Strong magnetoelastic coupling and local order–disorder transition at <italic>T</italic>* > <italic>T</italic><sub>N</sub> observed up to <italic>x</italic> = 0.10 in Y<sub>2−x</sub>Zn<sub>x</sub>Ru<sub>2</sub>O<sub>7</sub> pyrochlores.
Abstract The thermal stability of the cathode material against an electrolyte at operating temperature plays important role in fuel cell's performance. As such, compatibility tests most common used electrolytes with La 2– x Sr CuO 4 have been performed. chemical reaction between these two materials ranging from 800 to 1,000 °C was examined by X‐ray diffraction analyses. results show that all cases there is above 925 °C, making conventional cell fabrication non‐appropriate. However, we...
We present an extended x-ray absorption fine structure study of the pyrochlore ${\mathrm{Y}}_{2}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ (8--298 K). find evidence, on a local scale, significant magnetoelastic coupling at N\'eel temperature ${T}_{\mathrm{N}}\ensuremath{\sim}77\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ pointed out by huge Debye-Waller ${\ensuremath{\sigma}}^{2}$ factor deviation from correlated dependent Debye-like order behavior plus independent static contribution. Moreover, we...