Magnetic Aftereffects of Particles for High-Density Magnetic Recording Media

Thermal fluctuation aftereffect constant SV of particles for high-density magnetic recording media, whose mean volume V and coercive force Hc differed, were measured at the practical temperature range from 196 to 413 K. As for longitudinal magnetic recording particles, this experiment showed that the relationship of HC ∼ v-0.67 can be obtained among the activation volume v calculated from SV, HC, and mean volume V of magnetic particles. V/v is large, 4 to 50, and there is possibility that magnetization reversal caused by domain wall displacement will occur inside particles. On the other hand, unlike longitudinal magnetic recording particles, the relationship with perpendicular magnetic recording particles is HC ∼ v-1.9 and V/v is small, 1.4 to 2.3, surmised to have a mechanism of magnetization similar to that of single domain particles.