On magnetization reversal of Co-Cr films with perpendicular anisotropy

Based on a simple consideration, we show that the slope of the easy-axis lo op for perpendicular magnetization films is dominated by the lateral size o f a reversal unit. From the analyses of the slopes of Co-Cr films, we have estimated the lateral size of a reversal unit. The size becomes very large for the films grown and annealed at tow temperatures, indicating that there are strong exchange interactions between constituent magnetic grains due t o insufficient magnetically induced phase separation. We have also found a close relationship between the coercivity and the lateral size of a reversa l unit. All these results are discussed.