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MA: Fachverband Magnetismus
MA 15: Spin structures and Magnetic Phase Transitions
MA 15.5: Vortrag
Dienstag, 1. April 2014, 10:30–10:45, HSZ 403
Spin structures and electron lattice coupling in the double perovskite Sr2FeOsO6 — Avijit Kumar Paul1, •Peter Adler1, Manfred Reehuis2, Vadim Ksenofontov3, Binghai Yan1, Martin Jansen1, and Claudia Felser1 — 1Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany — 2Helmholtz-Zentrum für Materialien und Energie, Berlin, Germany — 3Johannes Gutenberg-Universität, Mainz, Germany
Double perovskites with an ordered arrangement of transition metal 3d and 4d or 5d sites show remarkable magnetic properties like half-metallic ferromagnetism below 400 K in Sr2FeMoO6 or ferrimagnetism with a high TC of 725 K in the insulator Sr2CrOsO6. We have studied the magnetic and electronic properties of insulating Sr2FeOsO6 by neutron powder diffraction, 57Fe Mössbauer spectroscopy and spin-polarized density functional theory calculations. Sr2FeOsO6 shows two magnetic phase transitions below 140 and 67 K, respectively. Similar as in related systems the spin structures reveal ferrimagnetic ordering of Fe and Os moments within the planes of the tetragonal crystal structure. Along c, however, two different spin alignment patterns are adopted which lead to overall antiferromagnetic behavior. Our experimental and theoretical results suggest a frustrated magnetic behavior, where the frustration is partially released by a Peierls-like lattice modulation and a switch of the spin structure below 67 K. Thus, Sr2FeOsO6 features an intimate interplay of lattice, spin and orbital degrees of freedom.