Dynamic performance of sequentially prepared magneto-optical TbFeCo disks

TbFeCo magnetooptical recording disks were prepared by sequential DC magnetron sputtering of Tb and FeCo, and the dependence of dynamic performance on the repeat distance, which was varied from 7 Å to 45 Å, was investigated. The carrier-to-noise ratio (CNR) of 54 dB measured at the dynamic test conditions of 3.7-MHz carrier frequency and 30-kHz bandwidth remained constant up to the repeat distance of 16 Å and then decreased linearly with further increase of the repeat distance. The writing sensitivity of the sequentially sputtered samples was improved by 1-3 mW, depending on the repeat distance, compared with alloy-sputtered disks. It is concluded that sequential sputtering is very attractive in the fabrication of TbFeCo films since it provides more sensitive and reliable magnetooptical recording media than alloy sputtering