ABSTRACT
This chapter presents a consolidated picture on the investigations reported on exchange bias (EB) phenomenon in bulk and ribbon forms of various ferromagnetic (FM) shape memory alloys belonging to the full Heusler family, mainly from the Ni-Mn-based subclass. In general, full Heusler alloys undergo a martensitic phase transition, that is, a first-order magneto-structural transition from a highly symmetric cubic austenitic phase to a low symmetry tetragonal/orthorhombic/monoclinic martensitic phase, as the temperature is lowered. In general, it has been found that the magnetism in the austenite phase of these alloys is simple to understand, but the magnetic state in the martensite phase is quite complex. In 1956, Meiklejohn and Bean discovered a new type of magnetic anisotropy, which was unidirectional in nature, as compared with the uniaxial anisotropy such as the magnetocrystalline anisotropy. Till date, EB effect has been exploited in various technological applications such as magnetoresistive random access memories and read heads of recording media.
