32 巻 (2008) 3 号 p. 260-264
The diameter and composition of magnetic crystal grains in a CoCrPt-SiOX perpendicular magnetic recording medium were investigated by using a transmission electron microscope (TEM) equipped with an energy-dispersive X-ray spectrometer (EDX). It has been shown that the composition of individual grains depends little on the grain diameter. The variations in the uniaxial anisotropy constant (Ku), the saturation magnetization (Ms), and the anisotropy field (Hk) are estimated from the composition for individual magnetic crystal grains. The thermal stability of magnetic crystal grains is discussed on the basis of the estimated KuV/kT values on the assumption that the magnetic crystal grains are magnetically separated.