Magneto-optical information storage device using photoconductive control element

[An] In an information storage and retrieval device comprising [a] an information storage plate of [a magnetizable] magneto-optic material, [means including a light beam] means for heating selected area of said storage plate, means to produce a magnetic field to effect storage within one of the heated areas of a value represented by one of two stable orientations, and means utilizing a magneto-optical effect for [recording and] retrieving information [in] from said storage plate, the improvement comprising a photoconductive layer on the magneto-optic material of the storage plate, and electrode means on said photoconductive layer, said heating means including the combination of optical means for positioning a spot of activating radiation on said photoconductive layer whereby a selected area of said photoconductive layer is rendered electrically conductive, said electrode means being connected to an electrical power source [to heat said layer] whereby a current can flow within said selected area and thermal energy is dissipated in said area which heats an adjacent area of the storage plate .