Magnetic materials and structures for thin-film recording media (invited)

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 H-c, with high M-s materials epitaxially grown on Cr underlayers. The second phase of thin-film 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 H-c but added the necessity of the reduction in the average grain size and grain size distribution width. The next and perhaps final phase of thin-film media development will be focused on the minimization of the magnetization thermal decay by the use of materials and designs that produce high KuV/k(B)T ratios. (C) 2000 American Institute of Physics. [S0021-8979(00)59808-9].