On Magnetic Properties of CoCrTa Perpendicular Magnetic Recording Media

抄録

The effect of Ta addition in Co_<83>Cr_<17> base composition was studied to investigate the origin of an increase in the coercivity. For this purpose, the perpendicular magnetic anisotropy of Co-Cr and Co-Cr-Ta films was measured before and after annealing at 550℃. The Co_<81.4>Cr_<16.6>Ta_2 film showed larger perpendicular anisotropy than the Co_<81>Cr_<19> film in the as-sputtered states. However, after the anneal, perpendicular anisotropy value of the two specimens were almost the same. The cause of this was interpretated as the enhauced segregation of solute atoms in the Ta added film in the as-deposited state. The change of d-spacings for the (0002) plane with the Ta addition was also studied. The linear increase of d-spacing with increasing Ta addition suggests that Ta is randomly distributed rather than segregated. This result implicates that the coercivity increase with Ta addition is not due to Ta segregation but due to enhanced segregation of Cr.