A theoretical investigation of Ferromagnetic Resonance Linewidth and damping constants in coupled trilayer and spin valve systems

Abstract

The ferromagnetic resonance intrinsic field linewidth ΔH is investigated for a multilayer system such as a coupled trilayer and a spin valve structure. The magnetic coupling between two ferromagnetic layers separated by a nonmagnetic interlayer will be described by the bilinear J 1 and biquadratic J 2 coupling parameters. The interaction at the interface of the first ferromagnetic layer with the antiferromagnetic one is account for by the exchange anisotropy field, H E. A general formula is derived for the intrinsic linewidth ΔH. The explicit dependence of ΔH with H E, J 1 and J 2 will be highlighted. Analytical expressions for each mode field linewidth are found in special cases. Equivalent damping constants will be discussed.