A micromagnetic study of the reversal processes in metal-evaporated tape

The morphology of ME tape undoubtedly affects its magnetisation reversal pr ocesses. It is therefore essential that a realistic model is used when simu lating the hysteresis of the film. A detailed 3D model representing the col umnar structure of ME tape is developed here and the reversal processes, in an assembly of columns, are investigated numerically. The results demonstr ate that reversal is affected by the strength of the exchange coupling para meter. Incoherent reversal occurs for weak coupling whereas increasing the strength brings about a high degree of co-operative reversal within columns . Strong exchange coupling and column demagnetising effects cause the momen ts to initially relax towards the long axes of columns. Then as the applied field is reduced the moments reverse at the column ends to form closure do mains. These results indicate a subtle relationship between magnetostatic a nd exchange interactions occurs during reversal. (C) 2001 Published by Else vier Science B.V.