Spike domains in single crystal nickel platelets

Magnetisation reversal processes often involve the nucleation and growth of spike domains with reversed magnetisation. Aspects of this process have been studied (a) experimentally in highly-perfect, single-crystal nickel platelets, using a high resolution magnetic colliod technique, and (b) theoretically by calculating energy changes in a simulated model of the domain structure. Spike domains have been observed in platelets which had thicknesses in the range O.1 to 15 μm, and sides from 20 μm to 1 mm. The behaviour was predominately magnetostatically controlled. Theoretical models based on evaluations of total energy variations, although giving fair agreement with experimental observations, showed very weak minima and indicated that the behaviour might best be explained by considering the equilibrium forces acting on a wall.