Regensburg 2007 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 14: Spin Systems and Itinerant Magnets

TT 14.16: Vortrag

Dienstag, 27. März 2007, 18:30–18:45, H19

Characterization and electronic structure calculations of the antiferromagnetic insulator Ca₃FeRhO₆ — •Volker Eyert¹, Udo Schwingenschlögl¹, Raymond Fresard², Antoine Maignan², Christine Martin², Ninh Nguyen², Christian Hackenberger³, and Thilo Kopp³ — ¹Institut für Physik, Universität Augsburg, 86135 Augsburg — ²Laboratoire CRISMAT, UMR CNRS-ENSICAEN(ISMRA) 6508, 14050 Caen Cedex, France — ³Zentrum für Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg, 86135 Augsburg

We investigate the antiferromagnetic insulating nature of Ca₃FeRhO₆ both experimentally and theoretically. Susceptibility measurements reveal a Néel temperature of T_N ≃ 20  K, and an effective magnetic moment of 5.3 µ_B per formula unit. Mössbauer spectroscopy strongly suggests that the Fe ions, located at trigonal prismatic sites, are in a 3+ high spin state. Transport measurements display a simple Arrhenius law, with an activation energy of ∼ 0.2 eV. The experimental results are interpreted with LSDA band structure calculations, which confirm the Fe³⁺ state, the high-spin/low-spin scenario, the antiferromagnetic ordering, and the value for the activation energy.