DEPENDENCE OF PERPENDICULAR COERCIVITY ON RESIDUAL-STRESS OF BA FERRITE ZNO BILAYERED FILMS DEPOSITED ON FUSED QUARTZ SUBSTRATE/

Ba ferrite films composed of perfectly c-axis oriented cystallites, pe rpendicular to film plane, were deposited on fused quartz sheets with ZnO underlayer at substrate temperature of 450 degrees C, It was found that the creation of microcracks due to the large residual stress in the films was sufficiently suppressed by depositing the ZnO layer at a substrate temperature of 450 degrees C and by reducing the thickness of ZnO layer. The stress also increased the perpendicular coercivity d ue to the magnetostriction effect. These results suggest that the thic kness of the Ba ferrite and ZnO layers should be reduced to decrease m agnetostrictive demagnetization to be suitable for the application to high density magnetic recording media.