Prediction of effective elements for magnetically induced phase separationin Co-Cr-based magnetic recording media

Thermodynamic calculations of the magnetically induced phase separation of the hcp phase in Co-Cr-based alloy systems, which is the origin of the comp ositional modulation observed in magnetic recording media, have been carrie d out. The magnetic and nonmagnetic terms in the Gibbs energy are evaluated from available thermodynamic data and Miedema's semiempirical values. It i s demonstrated that the phase separation in Co-Cr-X ternary alloys can be c lassified into four types, depending on the values of interaction energies between Co and/or Cr and X atoms. Existing magnetic data on Co-Cr-based rec ording media are discussed in terms of the phase stability of the hcp phase s. The present calculations would be useful for development of high-density magnetic recording media. (C) 2001 American Institute of Physics.