Studies On Manetocapacitance Effect In Inhomogeneous Media And Interfaces For Spintronic Applications

Abstract

newline Abstract newlineMagnetocapacitance (MC) is the change in capacitance of any dielectric material or an insulator, newlinecaused by an external applied magnetic field. The concept of spin accumulation (SA) newlinecapacitance can be explained using a magnetic multilayer model with current perpendicular newlineto the plane, which is well-known design that induces spin blocking. Spin build-up is seen newlineas an excess of electrons in one spin channel and an equivalent deficit in the other channel of newlinethe SA capacitor model with two spin channels, represented under the quasi-neutrality condition. newlineAs a consequence, the SA capacitor s charge is stored in the spin degree of freedom newlinerather than in coordinate space. The thesis investigates the basic nature of MC in selected newlinecategories of materials with a special focus on effect of inhomogeneity. newlineIn the beginning, we have put forth the introduction, motivation for the thesis and origin newlineof magnetocapacitance as depicted in literature. The dielectric relaxation mechanism in newlinesolids is thoroughly investigated in various reports. M.M Parish et al. proposed the idea newlineof magnetotransport in inhomogeneous conductors. They proposed methods to find out the newlinechange in magnetocapacitance (magneto-dielectric effect) due to inhomogeneity in the sample newlinewhich forms the basis of the thesis. newlineThe thesis is divided into two parts, the first two chapters formed the first part investigating newlinesign of MC using macro-spin approach and defect density change. The second part newlinehas selected categories of materials like 2-D solids, polymers, and thin-film heterostructures newlinedeveloping spin accumulation capacitance. We have investigated the sign of magnetocapacitance newlineand looked at its origin. Here, polyvinyl alcohol is taken as a polymeric dispersive newlinemedium with different proportions of iron particles embedded in it. The percentage of magnetic newlinecontent (Fe) was systematically varied to tune the interaction based on inter particle newlinevii newlinedistance. The sign of magnetocapacitance can be changed from positive to negative by establishing newlinet