A5085401925- Rare-earth and actinide compounds
- Magnetic Properties of Alloys
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Magnetic properties of thin films
- Iron-based superconductors research
- Advanced Condensed Matter Physics
- Advancements in Solid Oxide Fuel Cells
- Crystallization and Solubility Studies
- Theoretical and Computational Physics
- X-ray Diffraction in Crystallography
- Electronic and Structural Properties of Oxides
- Polyoxometalates: Synthesis and Applications
- Electrochemical sensors and biosensors
- Thermodynamic and Structural Properties of Metals and Alloys
- Magnetic Properties and Applications
- Nuclear materials and radiation effects
- Thermal Expansion and Ionic Conductivity
- Solid-state spectroscopy and crystallography
- Hydrogen Storage and Materials
- Catalytic Processes in Materials Science
- Nuclear Materials and Properties
- Ferroelectric and Piezoelectric Materials
- Crystal Structures and Properties
- Inorganic Chemistry and Materials
Universidad Politécnica de Madrid
2012-2022
University of Teramo
2021-2022
Universidad de Alcalá
2017
Universidad Carlos III de Madrid
2011-2012
Universidad de Cantabria
2006-2011
University of South Florida
2006
University of Lisbon
2004-2005
Universidade Estadual de Campinas (UNICAMP)
1999-2004
TARH (Portugal)
2004
Universidad Católica del Norte
1997
The oxygen ionic conductivity of apatite-type and increases with increasing content. ion transference numbers, determined by faradaic efficiency measurements at 973-1223 K in air, are close to unity for vary the range 0.96-0.99 other compositions. Doping iron results an fraction, which was evaluated Mössbauer spectroscopy correlates partial p-type electronic conductivities, whereas La-stoichiometric apatites stabilize state. Among studied materials, highest transport is observed where...
Up to now most of the magnetic ionic liquids containing tetrachloroferrate ion FeCl4 have evidenced a paramagnetic temperature dependence susceptibility, with only small deviations from Curie law at low temperatures. However, we report on physical properties 1-ethyl-3-methylimidazolium Emim[FeCl4], that clearly shows long-range antiferromagnetic ordering below Néel TN≈3.8 K. In addition, field magnetization measured 2 K is characterized by linear behaviour up around 40 kOe, while above this...
An unusual $4f$-superantiferromagnetic state characterized by simultaneous antiferromagnetic and spin-glass behaviors induced particle-size reduction is revealed in metallic nanoparticles ($\ensuremath{\approx}$9 nm) of TbCu${}_{2}$. The N\'eel temperature 46 K the glassy freezing below $\ensuremath{\approx}$9 governed a critical slowing down process. Neutron diffraction at 1.8 establishes superantiferromagnetism. latter settled nanoparticle moments mechanism provided surface spins.
The study of the magnetic properties depending upon mechanical milling ferromagnetic polycrystalline TbAl(2) material is reported. Rietveld analysis x-ray diffraction data reveals a decrease in grain size down to 14 nm and -0.15% variation lattice parameter, after 300 h time. Irreversibility zero field cooled-field cooled (ZFC-FC) dc susceptibility clear peaks ac between 5 K show that long-range structure inhibited favour disordered spin arrangement below 45 K. This glassy behaviour also...
Specific heat enhancement in several common nanocrystalline metals is established by comparison with their bulk counterparts. Measurements were carried out Fe, Cu, Ni and binary alloy LaAl(2). The excess specific evidenced as a low temperature peak below 65 K high slope above 150 K. experimental data are good agreement model which considers contributions from the grain boundary core atoms nanoparticles. This supported Raman spectroscopy measurements, showing softening of frequency phonon...
Measurements of specific heat, dc magnetic susceptibility, and Yb ${L}_{\text{II}}$ ${L}_{\text{III}}$ x-ray absorption near-edge structure (XANES) extended fine (EXAFS) on ${\text{YbAl}}_{3}$ milled alloys are reported. X-ray diffraction patterns consistent with a reduction in particle size down to 10 nm an increase the lattice strain up 0.4% for 120 h milling time. A decrease mean valence from 2.86 unmilled alloy 2.70 is obtained analysis XANES spectra. From spectra EXAFS region,...
Measurements of the magnetic, thermal, and transport properties ${\text{CeIn}}_{2}$ binary alloy are consistent with a paramagnetic-ferromagnetic transition at ${T}_{C}=22\text{ }\text{K}$. A discontinuity in magnetic entropy, electrical resistivity thermal expansion, huge anomaly specific heat 113 J/mol K $(\ensuremath{\Delta}{c}_{mag}=103\text{ }\text{J}/\text{mol}\text{ }\text{K})$, transition, observed. In addition, Arrott plots show negative slope low fields, field-cooling field-warming...
The structural state and static dynamic magnetic properties of TbCu2 nanoparticles are reported to be produced by mechanical milling under inert atmosphere. randomly dispersed as detected TEM retain the bulk symmetry with an orthorhombic Imma lattice Tb Cu in 4e 8h positions, respectively. Rietveld refinements confirm that produces a controlled reduction particle sizes reaching ≃6 nm increase microstrain up ≃0.6%. electrical resistivity indicates metallic behavior presence contribution...
A series of GdCu 2 nanoparticles with controlled sizes ranging from 7 nm to 40 has been produced via high-energy inert-gas ball milling. Rietveld refinements on the X-ray diffraction measurements ensure that bulk crystalline I m a structure is retained within nanoparticles, thanks employed low milling times t = 0.5 5 h. The analysis magnetic shows crossover Superantiferromagnetism (SAF) Super Spin Glass state as size decreases at NP ⟨ D ⟩ ≈ 18 nm. microstrain contribution, which always kept...