Münster 1999 – wissenschaftliches Programm

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AM: Magnetismus

AM 10: Postersitzung

AM 10.48: Poster

Dienstag, 23. März 1999, 16:15–20:00, F\"urstenberghaus

Step-Edge Magnetoresistance in La_0.7Ca_0.3MnO₃ Films — •M. Ziese¹, G. Heydon², R. Höhne³, P. Esquinazi³, and J. Dienelt⁴ — ¹Dept. of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom — ²Dept. of Engineering Materials, University of Sheffield, Sheffield S1 3JD, United Kingdom — ³Abt. Supraleitung und Magnetismus, Universität Leipzig, 04103 Leipzig — ⁴Institute for Surface Modification, 04318 Leipzig

As a first step towards easily fabricated magnetoresistance devices in planar technology, we have fabricated step edge structures in 25 nm thick La_0.7Ca_0.3MnO₃ films deposited on LaAlO₃ substrates. Step-edge arrays with 150 to 200 steps of height 100–200 nm and 20 µm step separation along [100] and [110] were fabricated by chemically assited ion-beam etching. The low-field magnetoresistance of the structures is large reaching 20% in a magnetic field of 0.1 T at 77 K. The dynamic conductivity indicates a spin-polarized tunneling mechanism with a spin-glass like interface.