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Magnetic Domain Memory Device that uses Ion Implanted Propagation Channels

IP.com Disclosure Number: IPCOM000051223D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Keefe, GE: AUTHOR

Abstract

Fig. 1 shows a serial access memory device that uses ion implantation to form propagation channels for inplane magnetic domains. Channels are formed in "as grown" garnet films 11 on substrate 8 with inplane anisotropy, high enough energy and dose to damage the exposed garnet film 11 and render it non-magnetic.

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Magnetic Domain Memory Device that uses Ion Implanted Propagation Channels

Fig. 1 shows a serial access memory device that uses ion implantation to form propagation channels for inplane magnetic domains. Channels are formed in "as grown" garnet films 11 on substrate 8 with inplane anisotropy, high enough energy and dose to damage the exposed garnet film 11 and render it non- magnetic.

Channels can be made as narrow as the lithography technique used permits. Fig. 2 is a sketch of randomly generated domains, displayed by ferrofluid, on 2.5 Mum wide channels on 5.0 Mum wide centers (formed by photolithography).

If E-beam lithography is used, submicron channels are possible, approaching domain wall widths, but without the instability problems associated with long domain walls. Also, these channels are formed by a single lithographic step, whereas the wall transition devices require two steps, one to form the magnetic pattern and another to form the wall stability step.

Magnetic domains can then be generated, propagated and detected by overlays of conductors. Fig. 3 shows a meandering propagation channel with overlaying conductors. Although, the garnet film was biaxial, experience has shown that walls formed between anti-parallel domains (shown in Fig. 5) are more stable than "head to head" domains, as in Fig. 4.

The more stable anti-parallel domain walls can also be formed in straight channels by using conductors that produce a field predominantly perpendicular to th...