High-Density Information Storage by Means of Magnetic Holography of Amorphous TbFe Thin Films (II)

Previously we reported the possibility of recording information by means of magnetic holography (using amorphous TbFe thin films as a hologram medium) onto a spot of diameter less than 1 mm, reconstructing data using the Faraday effect. However, we had not studied the basic characteristics of information storage in detail, and therefore were not able to make good-quality holograms with good reproducibility. Because reproducibility is the characteristic of greatest importance for recording, we studied the recording margin for information storage by magnetic holography. In addition, we considered the relationship between the power density of the two beams (object beam and reference beam) and the domain pattern (hologram). It was confirmed that the domain pattern is closely related to the beam density, and the recording margin depends on the information pattern. From these results, we were able to create good-quality holograms with satisfactory reproducibility.