MAGNETIC SUSCEPTIBILITY ANALYSIS IN Co/Pt MULTILAYERS

In this paper we report a study of magnetic properties and magnetization reversal in Co/Pt multilayer thin films. We compared the results obtained by different techniques for characterisation of the magnetic properties of Co/Pt multilayers (an induction method using computerised data acquisition and torsion magnetometry) in order to correlate these properties with structural and morphological features. Multilayered Co/Pt films with periods of (1.3-6.5) nm were produced by electrodeposition on (100)-textured Pt foils and (100)-textured Cu foils with a 50 nm Pt buffer layer. The effective magnetic anisotropy per unit volume and the coercive field were found to depend both on the Co layer thickness (tCo) and the Pt layer thickness (tPt). The susceptibility curves were analysed using the real-time Fast-Fourier-transform (FFT) method. In films with magnetic coupled layers and well-marked surface anisotropy, the AC susceptibility is connected with a series of harmonic components of AC magnetization induced by magnetic field. These peculiarities could be determined by the interaction between the moving domain wall and the local potential well formed by dynamic defects at interfaces. The Fast Fourier Transform (FFT) analysis of the susceptibility curves is proposed as a new technique for the study of multilayers