Hall-effect hysteresigraph for amorphous bubble-domain materials

A hysteresigraph is described which provides a much more rapid measurement of the coercivity of amorphous bubble films than any previously used method. This device utilizes the Hall effect to sense the film magnetization and has sufficient sensitivity and stability that coercivities as low as approximately 1 Oe can be readily measured. Although this device cannot provide an absolute measurement of saturation magnetization, approximate values of this quantity can be inferred from the saturation field indicated by the hysteresis loop. A probe-contact arrangement is employed which permits measurements to be made even on films having an insulating passivation layer.