**1.1 Introduction to ferrites**

Ferrites are the magnetic mix metal oxides comprising the ferric ions as an essential constituent, while in mineralogy or in metallurgy the term ferrites refer to that material having a cubic crystal structure of spinal mineral. The ferrites application has been known from ancient times for multiple centuries. Magnetite or ferrous ferrite is a naturally occurring ferrite. These are a class of mix metal magnetic oxide materials where ferric ions are present as a basic constituent. In metallurgy or mineralogy any materials containing spinal mineral of cubic crystal structure is referred as ferrites. The Chinese found its use in the loadstone (i.e. Fe3O4) due to its weak permanent magnetism for navigation purposes as early in the 12th century [1, 2].

Hilbert a German scientist, in 1909 reported first systematic study on the relation between magnetic and chemical properties of many iron oxides, but faced hurdles to identify its magnetic phases. However near to 1930s modern ferrites were investigated by Forestier, Hilppert and Wille for their structural, magnetic and electrical properties. Japanese scientist's attempted to study magnetic oxides from 1930s to 1935, Snoek and co-workers were studying the ferrites in 1936; they found that one of the important properties of ferrites to use as core for inductors is the loss tangent per permeability, so called loss-factor (**Figure 1**) [3].

They also investigated that loss can always be minimized by introducing an air gap and the permeability not effected adequately. This finding, led Snoke to develope manganese-zinc ferrite, of low loss and ultimate permeability. It was 1945, that Snoke coined the physical and technological applications of modern ferrites and a new field of science came into being. Since that time ferrites brought stormy revolution in electrical and electronic areas, to improve its capability and endurance [4**–**6].
