Preparation of Co-γFe₂O₃/NiO Thin-Film Media by Irradiation with Oxygen Ions

Abstract

A new plasma oxidization method was introduced into the fabrication process of Co-γFe₂O₃/NiO thin-film magnetic recording media in order to transform CoO-Fe₃O₄/NiO films into Co-γFe₂O₃/NiO films. It was found that remarkably effective oxidization was achieved by utilizing oxygen ions generated in an electron-cyclotron-resonance (ECR) microwave plasma, promoting oxygen generation through the Penning ionization effect using metastable He atoms, and neutralizing samples. In the conventional oxidization method, CoO-Fe₃O₄/NiO films were heated up to over 300°C, and kept for 1 to 2 hours in air. The new plasma oxidization method shortened the processing time to 10 seconds and lowered the process temperature to 150°C.