MOPS, a magneto-optic-photoconductor sandwich for optical information storage

A magneto-optic photoconductor sandwich, called MOPS, has been assessed as a memory medium for optical information storage. The present version of MOPS is composed of an epitaxial (Gd,Bi)3 (Fe,Ga)5O12 film and a Cu-doped CdS photoconductor film between coplanar In2O3/SnO2 electrodes. The chip contains 1.4×105 bits, requires 1 μW of optical power at 6328 Å for switching a memory cell in a magnetic field of 100 Oe and electric field of 1.2×104 V/cm, exhibits a read-out contrast of 21 : 1 at a read-out efficiency of 0.1%, and has a cycle time of ∼100 μs. MOPS has not been degraded by 107 switching cycles of arbitrary memory cells. No cross talk between neighboring bit sites has been observed.