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 20.2: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

Unusual finite-size scaling behavior of La_0.7Sr_0.3CoO₃ thin films — •Thorsten Schwarz^1,2, Dirk Fuchs¹, Peter Schweiss¹, and Rudolf Schneider¹ — ¹Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe — ²Universität Karlsruhe, Fakultät für Physik, D-76128 Karlsruhe

La_0.7Sr_0.3CoO₃ thin films were prepared by pulsed laser deposition on (001) oriented (LaAlO₃)_0.3(Sr₂AlTaO₈)_0.7 substrates with different film thickness, 400 nm > d ≥ 2.6 nm, and optimized with respect to their structural and magnetic properties. We carried out X-ray diffraction, transmission electron microscopy, Rutherford-backscattering spectrometry and energy dispersive X-ray absorption analysis in order to check the structural quality and chemical composition of the samples. The magnetic and electric properties were characterized by dc-SQUID and transport measurements, respectively. The microstructure and film magnetization seem to be homogeneous over the whole film thickness. Impurities or precipitations could not be observed. The decrease of the magnetic ordering temperature, T_C, with decreasing d, reflects finite-size effects with a critical scaling exponent of λ≈ 1, which is usually only expected for the 2 dimensional Ising model. Nearly the same scaling behavior was obtained for La_0.7Ca_0.3CoO₃ and La_0.7Ba_0.3CoO₃ thin films.