Characterization of the Magnetization Reversal of Bulk Electrical Steel and FeCoBSi Thin Film

Abstract

The aim of the research paper is to characterize the magnetization reversal of bulk electrical steel and FeCoBSi thin film samples by using MOKE microscope and further record the magnetic domain structure and magnetic hysteresis of samples along both easy and hard axes of magnetization.  MOKE microscopy is widely used in research field to characterize magnetic   properties   of materials used in integrated photonics and spintronic devices. The area under the hysteresis loop indicates whether the magnetic material is soft or hard. If the area is small, material is considered to be magnetically soft and vice versa.

Magneto-optical Kerr effect microscope or smoke is based on the principle of the Kerr    effect which describes that when light interacts with the non-transparent surface of magnetic material, it gets reflected and changes polarization. Ferromagnetic materials belong to the class of magnetic material in which, upon application of applied external magnetic field all the magnetic moments are aligned in same direction. Before the application of external field there exist certain regions in magnetic materials which are called domains. MOKE (Magneto-optical Kerr effect) Microscope is one of the widely used techniques to describe the magnetic domains pattern. The analysis of magnetic domain patterns gives information regarding nucleation, annihilation of magnetic domains and also interaction of domains with defects for instance grain boundaries. At saturation point, all the magnetic moments point in same direction superimposing a strong magnetism. Upon reducing the applied magnetization field to zero, material still exhibits some residual magnetization which is referred to as remanent magnetization.