Low Temperature Properties of Inhomogeneous Magnetic Multilayers

Abstract

System of two magnetic layers with nonuniform distribution of anisotropy parameter and exchange coupled by nonmagnetic spacer is studied by means of the Green function approach. Our attention is focussed on the elementary excitations and low temperature magnetisation behavior. The spin wave parameter B in the Bloch law T 3/2 is found as an oscillatory function of a spacer thickness. The eects of damping leading to non-zero line-width of ferromagnetic resonance peaks are also taken into account. As a result the dependence of resonance line-width on parameters characterizing system under consideration is obtained for the case of uniform anisotropy parameter and for quadratic distribution of this parameter in magnetic layers, respectively.

Spin Wave Characteristics of Inhomogeneous Ferromagnetic Layered Composites

“…Similar effect have been reported when existence of various sources of imperfection e.g. roughness in surface and interface region have been taken into account [9,14]. Formalism based on the Green function method presented above has been extended by introducing damping effects due to magnon-magnon interaction [13].…”

“…roughness in surface and interface region have been taken into account [9,14]. Formalism based on the Green function method presented above has been extended by introducing damping effects due to magnon-magnon interaction [13]. The spin wave characteristics can be then calculated employing the relaxation equation [14] including the damping term derived on the basis of results of Wesselinowa [15,16].…”

Low Temperature Magnetic Properties of Ferromagnetic Layered Composites

“…In order to calculate magnetic properties of the system it is convenient to apply the Green function method in Random Phase Approximation (RPA) [5,6]. Magnetisation of the layer ν in the multilayer system consisting of p of AB blocks is given by:…”

“…The method applied above can be modied [6] by introducing damping eects due to magnon-magnon interaction [8], calculated on the basis of relaxation equation [9]. As a result a continuous distribution of resonance intensity in Ferromagnetic Resonance (FMR) has been calculated, giving resonance spectra with non-zero line-width.…”