The calculation of output time decay in very-thin film disks

Low noise media are ,quid together with recent MR or Spin-valve heads for high density applications. To decrease the media noise, the magnetic unit, which is a grain or the activation volume in the film, must be shrunk. It is well known that the smaller the magnetic unir, the more susceptible it is to thermal fluctuations. This results in magnetization decay and in the broadening of the magnetic transition length “a” in a recorded medium. Both result in output decay.