A. Piñeiro

Reduction of the bulk modulus at high pressure in CrN

Nitride coatings are increasingly demanded in the cutting- and machining-tool industry owing to their hardness, thermal stability and resistance to corrosion. These properties derive from strongly covalent bonds; understanding the bonding is a requirement for the design of superhard materials with improved capabilities. Here, we report a pressure-induced cubic-to-orthorhombic transition at approximately 1 GPa in CrN. High-pressure X-ray diffraction and ab initio calculations show an unexpected reduction of the bulk modulus, K0, of about 25% in the high-pressure (lower volume) phase. Our combined theoretical and experimental approach shows that this effect is the result of a large exchange striction due to the approach of the localized Cr:t3 electrons to becoming molecular-orbital electrons in Cr-Cr bonds. The softening of CrN under pressure is a manifestation of a strong competition between different types of chemical bond that are found at a crossover from a localized to a molecular-orbital electronic transition.

Non-one-dimensional behavior in charge-ordered structurally quasi-one-dimensional Sr6Co5O15

We have synthesized Sr

Enhanced dimerization of TiOCl under pressure: spin-Peierls to Peierls transition.

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Fermiology and magnetism in weak itinerant ferromagnet CoS2: an ab initio study

Co

Electronic structure analysis of the quasi-one-dimensional oxide Sr6Co5O15 within the LDA+U method

_5

Ab initio study of the influence of nanoscale doping inhomogeneities in the phase separated state of La1-xCaxMnO3.

O

Effects of applied pressure in ZnV2 O4 and evidences for a dimerized structure

_{15}

Electronic structure of the antiferromagnetic phase of Sr2Co2O5

, a quasi-one-dimensional oxide, measured its magnetic properties and calculated its electronic structure by ab initio techniques. We have found strong evidence for its electronic and magnetic behavior not to follow the trend of its structural series. The magnetic coupling inside the CoO

Effect of spin fluctuations on the thermodynamic and transport properties of the itinerant ferromagnet COS2

_3

Pressure-induced metal–insulator transition in MgV2O4

chains is not purely ferromagnetic, the long-range coupling inside them is very weak. The Co moments are slightly canted due to their large orbital angular momenta being oriented along each particular quantization axis, that is different for each Co