FERRO-MAGNETIC MATERIAL while ferromagnetic materials lose magnetization. Ferri-magnetic (or ferrites) materials are complex oxides of iron and other metals. Knowledge of the Curie temperature of ferri-magnetic materials is of particular interest to the Physicists and the Engineers. The Unit enables one to trace the B-H loop (hysteresis ) of a ferromagnetic specimen using a C.R.O. A measurement of the area of the loop leads to the evaluation of energy loss in the specimen.