Počet záznamů: 1

Transition from the diamagnetic insulator to ferromagnetic metal in La.sub.1-x./sub.Sr.sub.x./sub.CoO.sub.3./sub..

  1. 1.
    0353298 - FZU-D 2011 RIV NL eng J - Článek v odborném periodiku
    Knížek, Karel - Jirák, Zdeněk - Hejtmánek, Jiří - Novák, Pavel
    Transition from the diamagnetic insulator to ferromagnetic metal in La1-xSrxCoO3.
    Journal of Magnetism and Magnetic Materials. Roč. 322, 9-12 (2010), s. 1221-1223 ISSN 0304-8853
    Grant CEP: GA AV ČR IAA100100611
    Výzkumný záměr: CEZ:AV0Z10100521
    Klíčová slova: LnCoO3 * GGA+U calculation * spin states transition
    Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
    Impakt faktor: 1.689, rok: 2010

    We have analyzed, using the theoretical GGA+U calculations, different configurations of spin states (LS, IS and HS Co3+) and proposed a model that accounts for magnetic and electric transport properties of perovskite cobaltites upon doping by charge carriers. In particular, it appears that the compositional transition from the diamagnetic LS phase of LaCoO3 to the ferromagnetic metallic IS phase in La1-xSrxCoO3 (x > 0.2) involves the same mechanisms as the high-temperature transition in pure LaCoO3. The process occurs gradually via a phase-separated state, where metallic IS domains stabilized through a charge transfer between Co4+ and Co3+ neighbors coexist with the Co4+ poor regions in the LS ground state (or, at higher temperatures, in mixed LS/HS state). This phase separation vanishes when doping in La1-xSrxCoO3 reaches x ~ 0.2, and a uniform IS phase, analogous to that in pure LaCoO3 in the high-temperature limit, is established.
    Trvalý link: http://hdl.handle.net/11104/0192582