Influence of Oxygen Content in Sputtering Targets on Co-Cr Film Properties

It is well known that the magnetic properties of Co-Cr film vary with several sputtering parameters, among which impurities in the sputtering gas and target are very important. However, the effect of impurities in the target has not previously been investigated. In this paper, we describe the effect of oxygen contained in sputtering targets on the magnetic properties of Co-Cr film. For low oxygen concentrations, the Hk and Hc ¿ of Co-rich magnetic particles were previously thought to be enhanced as the oxygen content was increased. However, with continued increases in oxygen content, the crystal orientation is so markedly degraded that the Hk and Hc ¿ become too small to enable use as a perpendicular recording medium. This effect is more pronounced for Co-Cr film thicknesses below 0.1 ¿m. Finally, it is concluded that the oxygen impurity concentration of the target should be as small as possible in order that Co-Cr media with excellent properties can be mass-produced.