Angular dependence of the perpendicular giant magnetoresistance of multilayers

Abstract

We present measurements of the angular dependence of the giant magnetoresistance in multilayers with the current applied perpendicular to the layer plane. The samples used are (${\mathrm{Ni}}_{80}$${\mathrm{Fe}}_{20}$/Ag/Co/Ag) multilayers sandwiched between superconducting underlayers and overlayers. The angle between the magnetizations of the ${\mathrm{Ni}}_{80}$${\mathrm{Fe}}_{20}$ and Co layers is continuously varied. We find that the current-perpendicular-to-the-plane magnetoresistance of these multilayers varies as 1-a ${\mathrm{cos}}^{2}$(\ensuremath{\theta}/2)+b ${\mathrm{cos}}^{4}$(\ensuremath{\theta}/2), where \ensuremath{\theta} is the angle between the magnetization of successive magnetic layers and b/a is between 0.1 and 0.3. We discuss the theoretical interpretation of this variation. \textcopyright{} 1996 The American Physical Society.