Patterned ferromagnetic meso and nano structures

Abstract

In this thesis, a comprehensive study of the effect of various geometrical parameters on the magnetization reversal process in patterned single and multilayer nanostructures is presented. The reversal mechanism in nanowires has been systematically investigated and a clear transition from coherent mediated reversal to curling mode is observed, as the film thickness is increased for fixed nanowire lateral dimensions. The role of dipolar coupling in pseudo-spin valve nanowire arrays has been systematically studied. Marked changes in the magnetization loops are observed, as the edge-to-edge spacing of the nanowire becomes comparable to the Cu film thickness. Laterally engineered nanowire array comprising of different width wires alternated in an array have been fabricated and characterized. Lastly, the role of film thickness and composition on the magnetization reversal process in nanodot structures has been extensively studied. The experimental results are supported by 2-D and 3-D micromagnetic simulations.