Increasing coercivity of CoCrTaPt/Cr thin film media by interdiffusion of Mn and Cu overlayers by low temperature annealing

Mn and Cu overlayers were studied with CoCrTaPt/Cr films on glass substrates. Low temperature postannealing reveals an increase in the in-plane coercivity of 700 Oe for Mn and 400 Oe for Cu. X-ray diffraction patterns indicate that the change in magnetic properties is unlikely due to the improvement of crystalline structure. It is suggested that the interdiffusion between magnetic layer and overlayer plays a key role in the coercivity increase. DM curves show reduced exchange coupling between grains. It is believed that during low temperature annealing, the diffusion of the overlayer atoms most likely occurs at the grain boundaries, which results in better segregation between grains that may lead to higher coercivity and lower media noise. (C) 1999 American Institute of Physics. [S0021-8979(99)51708-8].