Regensburg 2004 – scientific programme
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MA: Magnetismus
MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)
MA 13.116: Poster
Tuesday, March 9, 2004, 15:00–19:00, Bereich A
Doping and lattice effects in the half-metallic double perovskite Sr2CrWO6 — •Stephan Geprägs, Petra Majewski, Jan B. Philipp, Andreas Erb, Matthias Opel, Lambert Alff, and Rudolf Gross — Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Str. 8, 85748 Garching
The double perovskite Sr2CrWO6 and related compounds combine Curie-temperatures TC well above room temperature and a half-metallic ferromagnetic behavior, that is, they are expected to have a full spin polarization of the charge carriers at the Fermi level. This fact makes them very attractive for spintronic devices. In the compound Sr2FeMoO6 electron doping achieved by the substitution of Sr2+ by trivalent La3+ has been reported to lead to an increase of TC [1]. On the other hand, in Sr2CrWO6 the same substitution leads to a clear decrease of TC [2]. We have fabricated a series of high-quality polycrystalline samples of the two compounds with different La doping in order to compare carefully the effect on TC. All samples were characterized by x-ray powder diffractometry, magnetization and transport measurements. The results are of particular interest with respect to the physical mechanism stabilizing the high TC values: Within a double-exchange model one would rather expect an increase of TC with carrier doping, whereas a kinetic energy driven exchange mechanism is expected to result in a decrease of TC.
[1] J. Navarro et al., Phys. Rev. B 64, 092411 (2001).
[2] J. B. Philipp et al., Phys. Rev. B 68, 144431 (2003).