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Personalization Of Amorphous, Thin Film Bubble Domain Materials

IP.com Disclosure Number: IPCOM000081059D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Laff, RA: AUTHOR [+2]

Abstract

Local heating can result in a permanent change of state in amorphous bubble materials. The heating results in a change in the magnetic anisotropy factor, which is affected by altering the state of stress and/or degree of crystallization. No melting or other effect tending to cause surface deformation need occur, and the surface remains planar after the process.

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Personalization Of Amorphous, Thin Film Bubble Domain Materials

Local heating can result in a permanent change of state in amorphous bubble materials. The heating results in a change in the magnetic anisotropy factor, which is affected by altering the state of stress and/or degree of crystallization. No melting or other effect tending to cause surface deformation need occur, and the surface remains planar after the process.

In one example, an argon-ion laser acts to produce regions of easy bubble generation and containment of a width equal to the beam diameter in a GdCo film of two micron thickness on a fused quartz substrate. The wavelength of the laser beam, in this example, is approximately 5145 A, and the total power is approximately 0.25 watts. The beam is focused to a Gaussian beam diameter of 20 mu, and is swept at a speed of approximately 15 cm/sec. This represents an applied energy of <40 nanojoules/ cubic micron of film. At the stated speeds, most of the applied energy is lost to the substrates. The efficiency, for a given laser power, may be increased by reducing spot size and sweeping faster, until a point is reached at which the time at elevated temperature is insufficient to allow the necessary change in state to occur. As is evident, all of the "writing" criteria depend upon the thermal conductivity and heat capacity of the substrate and the film, and also upon the thermostatics and reaction kinetics of the state change in the film.

Fig. 1 shows bu...