Influence of the Co-doping of iron oxides on magnetic particle interactions

The effects of magnetic interparticle interactions are investigated on tapes made with iron oxide, chromium dioxide, and Co-surface-modified and Co-bulk-doped iron oxides. The magnetic interactions were experimentally studied with measurements of (a) the magnetization and demagnetization remanence curves, (b) the initial anhysteretic remanent susceptibility, and (c) the reputation of the magnetization cycles. The latter two techniques give the most suitable results for estimating the particle interactions, and a possible correlation between the results obtained with these methods is proposed. The Co-surface modified iron oxide particles show the weakest interaction effects. This is ascribed to the different orientation of the magnetic moments at the Co-modified surface layer of the particle