Preparation And Study On The Properties Of CoCrPt-based Alloy Recording Media For Hard-disk Using Glass Substrate

There have been three distinct stages in the development of magnetic materials and processes for thin-film media. The first era focused on designs for use with inductive heads. Vacuum sputter deposition techniques were developed to achieve high Hc , with high Ms materials epitaxially grown on Cr underlayers. The second phase of thin-film media development demanded media development demanded media optimized for the use with MR heads. Noise reduction through the decoupling of grains by chemical segregation of Cr at the grain boundaries proved effective. The introduction of giant magnetoresistance heads required low noise and high Hc but added the necessity of the reduction in the average grain size and grain size distribution width and smoother surface. Flatter and smoother glass substrates enable smoother surface of media on them. Because glass substrates can sustain high toughness and strengh even when they are extremely thin there has been uprated to match the hard-disk technology development. On the other hand, CoCrPt based recording media has been abroad investigated at the three different stage due to their good magnetic and chemical properties. In this paper, author laid a strong emphasis on the study of two types of films having great potential in high-density recording media using glass substrate. type I : CoCrPt alloy and type II : CoCrPtNb alloy. The coercivity of type I films is only 2000 Oe during room temperature deposited. However, Post-deposited annealed further improved the coercivity of the type I films up to 3600Oe and apparently decreased in intergranular exchange coupling and remenance-thickness product. For type II films using proper multilayer structure even at room temperature depositing, not only could the coercivity reach about 3000 Oe, but smaller grain sizes and narrower size distributions could be acheived. The coercivity of type II films also increased rapidly by high-temperature annealed. In order to obtain good properties of two types of films, these films were sputtered on glass substrate by RF magnetron sputtering apparatus and were systemic studied. 1)For CoCrPt magnetic recording media. author investigated the relation between argon pressure and magnetic properties of thin films, and studies the effect of Pt content in magnetic layer on magnetic properties. In addition, the effects of Cr underlayer thickness or Ti content of CrTi underlayer on microstructure and magneic properties of thin films were examined and the effect of post-deposited annealed on properties of films was analyzed and discussed. 2) For CoCrPtNb magnetic recording media. author discussed the effect of Nb content in magnetic layer (including as-deposited and annealed ), Ti content in CrTi underlayer and the thickness of carbon seedlayer on properties of thin films, and analyzed the cause for properties change of thin films.At last, two types of films for high-density magnetic recording media can be prepared on glass substrate by RF magnetron sputtering apparatus, type I: C / Co68Cr17Pt15 / Cr(Cr85Ti15) and type II : C / (CoCrPt)100-xNbx / Cr90Ti10 / C(16nm).