Inter-granular exchange coupling control by oxygen ratio in CoPtCrO perpendicular media

Abstract

Perpendicular recording is the most promising candidate to achieve areal densities exceeding 1 Tbit/in2. To achieve this goal, small grains with high uniaxial anisotropy and good magnetic isolation are required for the media. However, the optimum exchange coupling is also necessary to reduce DC-erase noise caused by the reversed grains due to the high demagnetization field. The high nucleation field Hn, and the low noise of the CoPtCrO perpendicular medium are attractive features. In this paper, the medium noise and exchange coupling correlation has been investigated by changing the oxygen ratio in the sputter gas.