A device for measuring the intrinsic hysteresis loop of a sample of magnetic material. Usually, the sample is magnetised in a 60 Hz field supplied by a solenoid and the intrinsic flux is detected by integrating the emf produced in an opposing pair of search coils, one of which surrounds the sample. The hysteresis loop may be displayed on an oscilloscope by feeding the X and Y plates with voltages proportional to the magnetising coil current and the integrated search coil emf respectively.