Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.3: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
La-doping in epitaxial thin films of LaxSr2−xCrWO6 — •Robert Geißler, Petra Majewski, Stephan Geprägs, Andrea Boger, Andreas Erb, Matthias Opel, Lambert Alff, and Rudolf Gross — Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Str. 8, 85748 Garching
Ferromagnetic double perovskites show high Curie
temperatures TC up to 600 K. For the system Sr2FeMoO6
(TC ≈ 420 K), it was shown that electron doping via the substitution
of
Sr2+ by La3+ increases TC by about 80 K in
polycrystalline
samples [1]. For Sr2CrWO6, the synthesis of bulk samples of electron
doped LaxSr2−xCrWO6 is difficult because of the preferential
formation of LaCrO3. However, due to the non-equilibrium growth
conditions
in pulsed laser deposition (PLD), LaxSr2−xCrWO6 with x=0.5
could
be grown epitaxially on SrTiO3 substrates with good crystalline quality
[2].
Here we report on the properties of LaxSr2−xCrWO6 films with
various
doping concentrations x. Using in-situ RHEED, the layer-by-layer growth
mode
is confirmed. The epitaxial thin films are analyzed by HRXRD to examine the
crystalline quality and to exclude parasitic phases. A systematic increase
of
the c-axis with increasing doping has been found. The magnetic properties
have been measured up to 800 K using a SQUID magnetometer to determine the
doping dependence of the Curie temperature TC(x).
This work is supported by the BMBF via grant no. 13N8279.
[1] C. Frontera et al., Phys. Rev. B 68, 012412 (2003).
[2] P. Majewski et al, J. Magn. Magn. Mater., in print (2004).