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Quelled Precession in Magneto Optic Films using Two Step Magnetic Field for Switching

IP.com Disclosure Number: IPCOM000082377D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

White, JM: AUTHOR

Abstract

A system is provided to speed up the switching speed of a magneto-optical material.

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Quelled Precession in Magneto Optic Films using Two Step Magnetic Field for Switching

A system is provided to speed up the switching speed of a magneto-optical material.

Most magneto-optical materials, and (Y(2.5)Gd(0.5))(Fe(4)Ga(1)O(12) is an example, are switched by applying a modulation signal in the form of a magnetic field to the latent magnetization of the material. In a magnetic material such as permalloy, the magnetization of the permalloy can be realigned with a new magnetic field H in a time less than a nanosecond. However, in a magneto-optic garnet film, such as (Y(2.5)Gd(0.5))(Fe(4)Ga(1))O(12), the magnetization will process about the resultant applied field H for many nanoseconds, so that the final state of the switch magnetic field does not stabilize for many nanoseconds.

Fig. 1 is employed to illustrate the theory explaining the quelling of precession in a magneto-optic film, using a two-step magnetic field for switching. The initial magnetization in the material is M(off) and M(on) is the state to which the magnetization is switched. H(o) is composed of the initial magnetic fields (both external and effective internal) at the time zero. Due to delta H(1), M starts to process about the resultant field H(1) at a precession frequency omega = gamma H(1), wherein H(1) is the vector sum of internal and external applied fields.

At a half-cycle later in the resonance of the precession frequency, M(off) is approximately at a position M(on), which is diamet...