High coercivity CoPtCr, CoPt films deposited at high power and high bias conditions for hard bias applications in magnetoresistive heads

We report, for the first time, coercivity values greater than 2000 Oe with Mrt values of 3.0 memu/cm(2) for Cr/CoP12Cr13 and Cr/CoPt20 bilayer films deposited by dc magnetron sputtering at room temperature. CoPtCr films sputtered at a deposition rate of 98 Angstrom/s and high bias voltage showed H-c of 1965 Oe with Mrt of 3 memu/cm(2), while CoPt films sputtered at 99 Angstrom/s and moderate substrate bias showed H-c of 2350 Oe with Mrt of 3 memu/cm(2). X-ray diffraction studies indicated that Co(10.0) and (11.0) texture leading to in-plane orientation of c axis are promoted in the films sputtered at high deposition rate and bias conditions. Furthermore, the grain-to-grain epitaxy between the Cr underlayer and the Co alloy layer as well as the dense Co grains growing in a columnar shape without voids resulted in higher H-c and Mrt without degradation of coercive squareness. Plots of H-c vs Mrt for films deposited under the optimum bias conditions offer a wide range of useful H-c and Mrt combinations for hard bias applications in magnetoresistive heads. (C) 1997 American Institute of Physics.