Magnetic anisotropy studies on FeNiCo/Ta/FeNiCo three layers film by layer sensitive ferromagnetic resonance technique

Abstract

Two ferromagnetic layers that are separated by a non-magnetic spacer have been deposited in the presence of an external DC magnetic field that has been applied in a mutually perpendicular direction during the deposition of each layer. This thin three-layer film of FeNiCo/Ta/FeNiCo was then studied by electron spin resonance (ESR) technique for different directions of the external magnetic field with respect to the film plane. Beside very anisotropic and strong two main modes, relatively well-resolved and very weak subsidiary peaks in ESR spectra were observed on low field side of the main modes for almost every direction of the external field. The anisotropic behavior as the field is rotated from the film normal towards to the film plane is due to strong demagnetizing field. However, two fold (axial) small anisotropies having 90 degrees phase shifts with respect to the peaks from two different layers were seen to originate from field-induced anisotropy. The small peaks are attributed to magnetostatics modes as well. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. © 2008 Elsevier B.V., All rights reserved.