US 4,583,200 AGranted

Magnetic memory device capable of memorizing information in a stripe domain in the form of a vertical Bloch line pair

AssigneeNEC Corporation

InventorsSusumu Konishi, Yasuharu Hidaka

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Abstract

In a magnetic memory device comprising a magnetic medium (21) having an easy axis of magnetization orthogonal to a principal surface of the medium, the medium has at least one stripe domain (20) surrounded by a domain wall which memorizes information in the form of a pair of vertical Bloch lines. Each pair is written in one end of the domain by supply of a local magnetic field to the one end when no magnetic bubble exists in the proximity of the one end. Each information is specified by absence or presence of each pair and successively transferred along the domain wall by a pulsed bias magnetic field. Readout operation is carried out at a preselected end of the stripe domain by supply of another local magnetic field to the preselected end to selectively chop the preselected end into a magnetic bubble only when each pair exists in the preselected end. Thus, presence and absence of each pair is converted into presence and absence of the bubble. Preferably, a negative Bloch line pair alone is memorized in the stripe domain. A pair of Bloch lines may previously be memorized prior to write-in operation of information.

Claims8

Dependent claims

A magnetic memory device capable of magnetically memorizing a plurality of information signals to produce an output signal representative of each of said information signals, by the use of a magnetic medium having a principal surface and an easy axis of magnetization orthogonal to said principal surface, said magnetic memory device comprising:

controllably generating means for controllably generating at least one magnetic domain of a stripe shape that is surrounded by a domain wall laid in substantial parallel to said easy axis and having wall magnetization along said domain wall and that has a pair of end portions opposite to each other and an intermediate portion between said end portions;
write-in means adjacent to a predetermined one of said end portions and responsive to said each information signal for writing said each information signal in said domain wall in the form of a first pair of vertical Bloch lines intersecting said domain wall;
detecting means adjacent to a specific one of said end portions for detecting said first vertical Bloch line pair to produce said output signal;
and
transferring means for transferring said first vertical Bloch line pair from said predetermined end portion to said specific one of the end portions through said intermediate portion within said domain wall.

2 more elements

Dependencies are inferred from the claim text.