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TT: Tiefe Temperaturen

TT 24: Postersitzung III: Korrelierte Elektronen, ”Orbital Physics”

TT 24.56: Poster

Mittwoch, 10. März 2004, 14:30–19:00, Poster A

Magnetic ordering in the trigonal chain compounds Ca₃CoRhO₆ and Ca₃FeRhO₆ — •Udo Schwingenschlögl, Volker Eyert, and Ulrich Eckern — Theoretische Physik II, Institut für Physik, Universität Augsburg, 86135 Augsburg

Low-dimensionality and frustration effects in compounds containing magnetic ions have attracted a lot of attention since long owing to the expectation of a variety of fascinating properties. Much interest has focused on systems, where the chains are arranged in a triangular lattice. Continuing recent work on the prototypical compound Ca₃Co₂O₆ [1] we present the results of augmented spherical wave (ASW) electronic structure calculations for the closely related compounds Ca₃CoRhO₆ and Ca₃FeRhO₆. In accordance with experimental data we find strong intrachain magnetic coupling of high-spin 3d-metal sites via the d-states of the interjacent low-spin rhodium sites resulting in the observed ferromagnetic and antiferromagnetic order in Ca₃CoRhO₆ and Ca₃FeRhO₆, respectively. Considerable hybridization with the O 2p states leads to polarization of the latter and the formation of extended magnetic moments, which are well localized at the high-spin sites.

[1] V. Eyert. C. Laschinger, T. Kopp, and R. Frésard, submitted to Chem. Phys. Lett.