THE INFLUENCE OF SUBLAYER THICKNESS ON GMR AND MAGNETIZATION REVERSALIN PERMALLOY CU MULTILAYERS/

It has been shown that in Py/Cu (Py = Ni87Fe17, permalloy) multilayers obtained by face-to-face sputtering technology, two well-separated an tiferromagnetically coupled ranges can be found centered at d(Cu) appr oximate to 1 and 2 nm, respectively, However, d(Cu) values correspondi ng to the largest field sensitivity of the GMR effect are different fr om those for which the strongest antiferromagnetic exchange coupling h as been found. With decreasing Py thickness, the magnetic properties b ecome strongly influenced by the magnetisation fluctuations, We attrib ute this effect to the presence of compositionally intermixed interfac es. Changes in the magnetic properties and magnetoresistance as a func tion of Py thickness are analysed in terms of evolution from paramagne tic through superparamagnetic to ferromagnetic behaviour of these inte rmixed regions.