Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.147: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
X-ray Magnetic Circular Dichroism (XMCD) study of Re and W in ferrimagnetic double perovskites Sr2CrMO6 (M = Re, W) — •S. Gepraegs1, P. Majewski1, O. Sanganas1, M. Opel1, R. Gross1, F. Wilhelm2, A. Rogalev2, and L. Alff3 — 1Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner-Str. 8, 85748 Garching — 2European Synchrotron Radiation Facility (ESRF), 6 Rue Jules Horowitz, BP 220, 38043 Grenoble, Cedex 9, France — 3Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt
Among the ferrimagnetic double perovskites in the compounds Sr2CrReO6 and Sr2CrWO6 high Curie temperatures well above room temperature have been found experimentally and half-metallicity (resp. pseudo-half-metallicity) was predicted by band-structure calculations. These strong ferromagnetic order can at least qualitatively be understood within a generalized double exchange or kinetic energy driven exchange model where the itinerant electrons mediate an antiferromagnetic alignment between the Cr or Fe and the W or Re moments.
We have measured Re and W 5d spin and orbital magnetic moments in the double perovskites Sr2CrReO6, Sr2CrWO6, and Sr2FeWO6 by X-ray magnetic circular dichroism (XMCD) at the L2,3 edges. Our results are in good agreement with recent band-structure calculations. We find that the Curie temperature in the double perovskites A2BB′O6 scales with the spin magnetic moment of the ’non-magnetic’ B′ ion. This work was supported by the DFG (GR 1132/13), the BMBF (project no. 13N8279), and the ESRF (HE-1658, HE-1882).