Progress report on square-hysteresis loop ferrites

A previous paper (Annual Report of the Conference on Electrical Insulation, 1952 meeting, p. 51) contained a brief account of a new phenomenon in the field of ferromagnetics: the spontaneous formation of rectangular hysteresis loops in ceramic ferric-oxide bodies. The rectangular hysteresis loop originates in these ferrites directly with no need for annealing, grain orientation or external stress. The spontaneous development of a rectangular hysteresis loop contradicts the usual conception of the behavior of ferromagnetics. Tae phenomenon is now being studied, at MIT from a theoretical viewpoint. In the present paper experimental data are reported as they have accumulated at General Ceramics during the last year.