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 substrate s. Low temperature postannealing reveals an increase in the in-plane coerci vity of 700 Oe for Mn and 400 Oe for Cu. X-ray diffraction patterns indicat e 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. D M curves show reduced exchange coupling between grains. It is believed that during low temperature annealing, the diffusion of the overlayer atoms mos t likely occurs at the grain boundaries, which results in better segregatio n between grains that may lead to higher coercivity and lower media noise. (C) 1999 American Institute of Physics. [S0021-8979(99)51708-8].