Investigation of perpendicular magnetic films by means of soft X-ray magnetic circular dichroism spectroscopy

Nowadays, the magnetic data storage technology is supporting our highly information-oriented society. High storage packing-densities in hard disk drives (HDD) have been desired since the invention and remarkable progress has been made. After the perpendicular recording technology was proposed about 30 years ago, intensive studies have been made to realize this concept all over the world. Very recently, in December, 2004, the first HDD system based on perpendicular recording was announced to start mass production in Japan, There are many candidate materials for perpendicular magnetic recording media. In this review, the investigation of perpendicular magnetization films such as multilayered films of and rare-earth transition metal amorphous films are introduced. The measurements were performed by soft X-ray absorption and magnetic circular dichroism spectroscopy (XAS-MCD), which gave us information on the unoccupied electronic and spin states of individual elements in the materials. It is shown that XAS-MCD spectroscopy is a useful experimental method to study the perpendicular magnetization films. (author)