Research/Patents/US 4424580
US 4424580ACTIVE SECRECY ORDER

METHOD AND APPARATUS FOR GENERATING ELECTRON SPIN REVERSAL IN FERRIMAGNETIC MATERIAL

Assignee

PRECISION DATA, INC., A CORP. OF CA

Filed

May 6, 1981

Granted

Jan 3, 1984

Location

MOUNTAIN VIEW CA US

Abstract

Methods and apparatus for reversibly altering magnetic characteristics or domains of ferrimagnetic material by photomagnetic means, particularly by electron spin reversal (spin-flip). Photomagnetic electron spin reversal and inversion creating cylinder domains and their surrounding toroid domains of oppositely directed intrinsic magnetization in ferrimagnetic thin film material are achieved by means of signal modulated circularly polarized laser radiation. Three different stable conditions are detectable. The invention has particular application as a fundamentally new aproach to erasable digital data storage, providing means and methods for photomagnetically alterable and erasable data storage which can be detected by observing polarization of optical radiation directed through the ferrimagnetic material.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Oct 19, 1981

Rescinded

Never rescinded

Duration

44y 8mo — still active

This secrecy order has no recorded rescission date in USPTO records. The order may still be legally in force, or rescission data may not be publicly available.

Inventor

  • 1CARL H. BECKER

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Back to patent indexSource: USPTO 35 USC §181 secrecy order records