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 bilay er films deposited by dc magnetron sputtering at room temperature. CoP tCr films sputtered at a deposition rate of 98 Angstrom/s and high bia s voltage showed H-c of 1965 Oe with Mrt of 3 memu/cm(2), while CoPt f ilms 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 indica ted that Co(10.0) and (11.0) texture leading to in-plane orientation o f c axis are promoted in the films sputtered at high deposition rate a nd bias conditions. Furthermore, the grain-to-grain epitaxy between th e 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 M rt 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 magne toresistive heads. (C) 1997 American Institute of Physics.