Half Tone Production in Magneto-optic Image

Abstract

The feasibility of the half tone production of magneto-optic image is presented.The recording medium is ferromagnetic thin film (82% Ni-Fe permalloy) prepared by vacuum evaporation. The tonal image which was caused by the circular magnetization or radialmagnetization is detected by longitudinal Faraday effect. In order to produce both magnetizations, two methods were examined: one was to get the concentric circular magnetizationby magnetic field generated from direct current through a fine copper wire and the other wasto get the radial magnetization by the magnetic field generated from a flat coil.
The tonal part in the image was considered that those directions of magnetization fixed by magnetic evaporation effect took various forms of distribution similar to that of external magnetic fields.
The intensification of double layer evaporation as described in the previous paper was also tried and this procedure was applicable for curved distribution of magnetization.