In this paper we will present a study of magnetic viscosity as a function of applied field of CoCrTa/Cr in-plane media. The viscosity versus applied field curves (viscosity curves) of the samples exhibit a sharp peak at remanence coercivity (Hcr). Their activation volume was found to be close to the physical volume of the grains. The experimental viscosity curves are fitted to the simulated curves obtained by using an analytical model of Chantrell et al. [1]. Our simulation results give better understanding of the roles of the distribution function and the energy barrier in the formation of the viscosity curves. Based on the results, the relation between the peak position of the viscosity curves and the values of coercivity and remanence coercivity are explained.

A measurement system based on the magneto-optic Kerr effect was developed in order to study magnetic thin films for applications in recording media. The sample can be rotated in the magnetic field by using two Al mirrors. Two components of the magnetization can be measured for different directions and magnitudes of the applied field. The measurement performance was shown by experiments on sputtered Co-Cr films. The results are in agreement with those of biaxial VSM experiments performed on the same sample. Preliminary results suggest that rotation of the spins, which mainly occur for larger fields, oppose the reversal of the magnetization.

The influence of the demagnetization field on the magnetic after-effect of Co-Cr media is discussed. The demagnetizing field of as-sputtered Co-Cr was changed into block-shaped micro structures by lithographic processes. This process does affect the shearing of the perpendicular hysteresis curve but not the intrinsic magnetic properties. A linear relation was obtained between the coefficient of magnetic viscosity and the slope of the hysteresis curve. >

In this paper we describe the nucleation and growth of thin CoCr layers on different substrates and seedlayers. Especially the presence and formation of the initial layer is considered, and corresponding growth mechanisms are proposed. The magnetic properties of these layers have been analyzed by in-plane VSM and by anomalous Hall effect (AHE) measurements. Even layers as thin as 5nm are shown to exhibit a perpendicular magnetic anisotropy. For a high coercive CoCr film the formation of dot-like domains is shown by the Bitter-colloid/SEM technique.

Chromium sulfides Cr1−xS with 0 ⩽ x ⩽ 0·12 have been investigated by high- and low-temperature X-ray diffraction, differential thermal analysis and magnetic methods. A tentative phase diagram is derived which explains all the anomalies in the thermal behaviour observed previously.