PUB - Publikationen an der Universität Bielefeld

The (Ni(80)Fe(20i)Col);CuAgAu/Co2 asymmetric sandwiches have been examined for different sublayer thicknesses. Magnetoresistance, magnetooptical Kerr effect and alternating gradient magnetometry measurements showed that for 1.2 nm less than or equal to d(CuAgAu) less than or equal to 1.6 nm our trilayers are antiferromagneticatly coupled whereas for d(CuAgAu) greater than or equal to 1.9 nm the coupling between Ni80Fe20i Col and Co2 is ferromagnetic. The ferromagnetic coupling strength oscillates with CuAgAu thickness with a period of 1 nm. The appearance of the ferromagnetic interlayer coupling for d(CuAgAu) greater than or equal to 1.9 nm and its oscillatory character result from the interplay between RKKY-Iike exchange coupling and the magnetostatic orange-peel coupling. The values of the ferromagnetic coupling field between Ni80Fe20iCoI and Co2 for a constant CuAgAu thickness can be either enhanced or reduced depending on the ratio between Col, Co2 and Ni80Fe20 thicknesses. In spite of oscillatory ferromagnetic coupling strength for d(CuAgAu) greater than or equal to 1.9 nm our trilayers show the GMR amplitude of about 10% and the GMR field sensitivity of about 5%/Oe at room temperature being very promising from the application point of view. (C) 2003 Elsevier B.V. All rights reserved.