Browse Prior Art Database

Memory Device

IP.com Disclosure Number: IPCOM000090179D
Original Publication Date: 1969-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Mazzeo, NJ: AUTHOR [+2]

Abstract

This nondestructive readout magnetic film memory device, drawing A, uses a three-part slotted word line to prevent loss of stored information by wall creep effects during innumerable readout operations. Slotted word line 1 has a middle strand 2 and two outer strands 3. Bit line 4 is plated on both sides with a permalloy film 5 which provides the magnetic bit storage medium. The film 5, drawing B, is separated by insulating layer 6 from line 1 and by insulating layer 7 from ground plane 8.

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Memory Device

This nondestructive readout magnetic film memory device, drawing A, uses a three-part slotted word line to prevent loss of stored information by wall creep effects during innumerable readout operations. Slotted word line 1 has a middle strand 2 and two outer strands 3. Bit line 4 is plated on both sides with a permalloy film 5 which provides the magnetic bit storage medium. The film 5, drawing B, is separated by insulating layer 6 from line 1 and by insulating layer 7 from ground plane 8.

During writing operations line 4 and outer strands 3 of line 1 are coincidentally energized to magnetize film 5 in the desired direction transversely of line 4 for storing a selected-binary digit.

The stored bit occupies a relatively wide space in film 5, with its domain walls being at least as far apart as the full width of line 1.

During readout, however, only the middle strand 2 is energized. The read field which this produces is not as extensive as the domain in which the bit is stored, even though the read pulse can have the same amplitude as the word write pulse.

This NDRO memory device has the following advantages. Within any given bit storage cell, all of the magnetic vectors point in the same direction during the quiescent state of the device. Hence application of the read field does not produce any counter rotational effects of these vectors which would decrease the output signal from the interrogated cell. The read field is effectively limited to an area...