NDLI: Thin films of MnBi for beam addressable beam alterable optical memory applications

Content Provider	IEEE Xplore Digital Library
Author	Chen, D. Ready, J.F. Bernal G., E.
Copyright Year	1967
Description	Author affiliation: Honeywell Research Center, Hopkins, Minn. (Chen, D.)
Abstract	Laser Curie-point writing on thin magnetic films in conjunction with a magneto-optic readout technique provides a number of advantages over presently available mass memory systems. This approach, however, imposes stringent requirements on the material properties of the film memory plane. We have found that thin films of MnBi possess many unusual physical properties and are particularly suitable for this application. Films prepared on mica substrates typically have a specific Faraday rotation of5 \times 10^{5}degrees/cm, and an absorption coefficient of2 \times $10^\{5\}cm^{-1}for$ 6328Å wavelength, permitting a readout rate of 109 bits/sec at 1 mw laser power level using available detectors. Heating of a spot 3 microns in diameter in a 1000Å thick film with a 10-mw Gaussian laser beam has been calculated using the heat flow equation. The result shows that the entire spot can be raised to above the Curie temperature (345°C) from 20°C at the end of a 1µ sec laser pulse. For a 106 $bits/cm^{2}packing$ density, heating at adjacent spots is negligible. Experimentally, we have been able to write a manually scanned line of 3.7µ width with a 10-mw laser on a SiO coated Mn, Bi film in air. To reduce the required writing magnetic field, films of discrete squares of 4µ sides and 12µ separation have been prepared. Calculations show that the writing magnetic field in this case can be as low as 10 Oe. Analytical and experimental results as well assystem considerations will be presented.
Starting Page	96
Ending Page	96
File Size	115186
Page Count	1
File Format	PDF
DOI	10.1109/IEDM.1967.187853
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	1967-10-18
Publisher Place	USA
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Optical films Optical beams Magnetic films Laser beams Writing Heating Magnetic fields Laser applications Read-write memory Material properties
Content Type	Text
Resource Type	Article

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