FeAlN/SiO2 and FeAlN/Al2O3 multilayers for thin-film recording heads (invited)

Abstract

FeAlN films and FeAlN/SiO2 and FeAlN/Al2O3 multilayer films have been studied as potential high moment head materials. The magnetic properties of FeAlN films on glass are similar to those of FeN, but the Al decreases the saturation magnetostriction constant and shifts the minimum coercivity point to a higher N content. Compared with the single layers, FeAlN/SiO2 and FeAlN/Al2O3 multilayers have reduced coercivity, and their permeance spectra have increased roll-off frequencies. In the multilayers, a 4πMs of 18–22 kG, a coercivity of 0.3 Oe, and a saturation magnetostriction constant smaller than 2×10−6 are obtained. These magnetic properties are very stable to annealing up to 360 °C, due to the presence of the Al. FeAlN and FeN single and multilayers show localized corrosion at defect sites when subjected to extended periods of a high-humidity/high-temperature test, but the corrosion is slow. Films with comparable properties to those on glass have been obtained on n-Si substrates; films on alumina-TiC substrates have also been studied.