arXiv subjects

V. Pardo

Publications and source records attributed to V. Pardo.

40 records · Page 3Linked to original sources

arXiv2006

First principles study of the spin state transitions in GdBaCo$_2$O$_{5.5}$

Electronic structure calculations were carried out on the compound GdBaCo$_2$O$_{5.5}$. The electronic structure variation with a change in the spin state of the Co$^{3+}$ ion in an octahedral environment has been studied. All the insulating phases are described and possible scenarios for the metallic ones are presented. Orbital ordering is shown to take place and the electronic structure leading to it is determined. The Ising-like anisotropy shown experimentally can be predicted. Also, big unquenched orbital angular momenta are calculated and their origin is described.

cond-mat.str-el↗

arXiv2005

Effects of Sr doping on the magnetic properties of Sr$_x$Ba$_{1-x}$CoO$_3$

Magnetic properties of the Sr-doped BaCoO$_3$ are explained on the basis of ab initio calculations and the analysis of experimental literature. Formation of magnetic clusters bigger than in the parent compound and increase in the blocking temperature are observed. Superparamagnetism remains at room temperature. The possibility of tuning the size and properties of the magnetic clusters with doping is explored.

cond-mat.str-el↗

arXiv2004

Evidence for magnetic clusters in BaCoO$_3$

Magnetic properties of the transition metal oxide BaCoO$_3$ are analyzed on the basis of the experimental and theoretical literature available via ab inito calculations. These can be explained by assuming the material to be formed by noninteracting ferromagnetic clusters of about 1.2 nm in diameter separated by about 3 diameters. Above about 50 K, the so-called blocking temperature, superparamagnetic behavior of the magnetic clusters occurs and, above 250 K, paramagnetism sets in.

cond-mat.str-el↗

arXiv2004

Magnetic structure and orbital ordering in BaCoO3 from first-principles calculations

Ab initio calculations using the APW+lo method as implemented in the WIEN2k code have been used to describe the electronic structure of the quasi-one-dimensional system BaCoO3. Both, GGA and LDA+U approximations were employed to study different orbital and magnetic orderings. GGA predicts a metallic ground state whereas LDA+U calculations yield an insulating and ferromagnetic ground state (in a low-spin state) with an alternating orbital ordering along the Co-Co chains, consistent with the available experimental data.

cond-mat.str-el↗