A New Type of Magneto-Optic Readout Head

A "domain-modulation-type optical reproduction head" is reported, in which the signal field is transmitted through a high permeability film to a readout magnetic film, which enlarges the domain and enables reproduction by laser light. Magnetic garnet was used as the readout film, and (60 to 300 ¿m thick) Permalloy as the high permeability film. In tests, the modulated domain width of the garnet was greater (approximately 4 ¿m) than for the Permalloy, suggesting the possibility for high-resolution laser reproduction.