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Isotropic Film Read Only Memory

IP.com Disclosure Number: IPCOM000093869D
Original Publication Date: 1966-Mar-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Johnson, C: AUTHOR

Abstract

As shown in A, a read-only memory comprises isotropic, or unoriented, thick magnetic films 1 and 3. Each defines an information bit slot and is coupled between word drive line 5 and bit sense loops 7 and 9, respectively, arranged in squared figure-eight configuration.

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Isotropic Film Read Only Memory

As shown in A, a read-only memory comprises isotropic, or unoriented, thick magnetic films 1 and 3. Each defines an information bit slot and is coupled between word drive line 5 and bit sense loops 7 and 9, respectively, arranged in squared figure-eight configuration.

A first binary state, stored 1, is defined in a thick magnetic film by the normal random orientation of domains in a lowest energy state as illustrated in B. A second binary state, stored 0, is defined when a thick magnetic film is decoupled from the associated sense loop by permanent magnet 11. When decoupled, the domains in a thick magnetic film are aligned in the direction of magnetization of magnet 11 as illustrated in C. During interrogation, word line 5 is energized by a unidirectional pulse.

The magnetization of domains in decoupled film 3, stored 0, is unaffected. On the other hand, the magnetization of coupled film 1, stored 1, aligns with a magnetic field generated by word line 5 and induces a voltage in the associated sense loop 7. The isotropic characteristics along with the high demagnetization forces inherent in thick magnetic film 1 accelerates return of the domains to the lowest energy state upon completion of the interrogation cycle.

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