Effects of the exchange stiffness constant and distribution on the recording characteristics of perpendicular media

The relationship between the exchange stiffness constant of a perpendicular medium- and high-density recording characteristics was investigated by micromagnetic simulation. As the exchange stiffness increases, larger magnetic clusters are formed in the ac-erased magnetization state. The shortest recordable bit length of the medium corresponds to the cluster size observed in the ac-erased magnetization state. The slope of the magnetization loop also correlates with the average magnetic cluster size.