On magnetization reversal of Co-Cr films with perpendicular anisotropy

Based on a simple consideration, we show that the slope of the easy-axis loop for perpendicular magnetization films is dominated by the lateral size of 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 to insufficient magnetically induced phase separation. We have also found a close relationship between the coercivity and the lateral size of a reversal unit. All these results are discussed.