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 20.38: Poster

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

Magnetoresistance in bicrystal Fe₃O₄ thin films — •A. Bollero¹, M. Ziese¹, P. Esquinazi¹, K. Dörr², and I. Mönch² — ¹University of Leipzig, Division of Magnetism and Superconductivity, Linnéstrasse 5, 04103 Leipzig — ²Institute for Metallic Materials, IFW Dresden, Helmholtzstr. 20, 01069 Dresden

Epitaxial and polycrystalline Fe₃O₄ films can have a large high-field magnetoresistance (absent in bulk material) attributed to electron transfer across the antiphase boundaries (APBs) [1]. In the present work an epitaxial magnetite (Fe₃O₄) film has been deposited by the pulsed laser deposition (PLD) technique on a bicrystal substrate. Magnetoresistance measurements on patterned stripes (width = 20 µm) across the bicrystal grain boundary have not revealed a distinguishable grain boundary contribution, by comparison with similar experiments performed on manganese perovskites [2]. Post-annealing of the film leads to a significantly enlarged high-field magnetoresistance with decreasing temperature for T < T_V (T_V: Verwey transition temperature). Decreased resistivity and coercivity values are obtained after annealing of the film which is attributed to a reduction in the density of APBs.
M. Ziese and H. J. Blythe, J. Phys. Cond. Matt.: 12 (2000) 13.
K. Steenbeck, T. Eick, K. Kirsch, H.-G. Schmidt and E. Steinbeiß, Appl. Phys. Lett. 73 (1998) 2506.