Non-collinear magnetization configuration in interlayer exchange coupled magnetic thin films

Abstract

Element specific magnetic hysteresis loops of the interlayer exchange coupled CoFeB/Ru/[Co/Ni](4) structure were measured utilizing x-ray magnetic circular dichroism. It was found that the Co/Ni multilayer and the CoFeB layer have Ru thickness dependent oscillatory interlayer coupling. Due to its interlayer coupling with the perpendicularly magnetized Co/Ni multilayer, the CoFeB magnetization direction is slightly tilted out-of-plane from its in-plane magnetic easy axis. Quantitative measurements show that the tilting angle is small (< 12 degrees) and that a small in-plane magnetic field (similar to 50 Oe) applied to this structure will result in a completely in-plane CoFeB magnetization. (C) 2011 American Institute of Physics. [doi:10.1063/1.3634027]