Magnetization reversal in nanostructured permalloy rings

Summary form only given. Recently, nanostructured rings have attracted much attention in the application of MRAM design because the shape anisotropy makes it easier to generate a closure flux loop spin configuration, which avoids the field leakage and therefore enhances the data storage density. A Permalloy ring with the size of 187.5 nm outer diameter, 112.5 nm inner diameter, and 30nm thickness has been studied by means of micromagnetic simulation. The authors show the hysteresis loop of the ring from our simulation result, with schematic pictures used to represent the stable states I, II, and III of the plateaus.