US 4,731,752 AGranted

Bloch line memory device with stripe domain stabilizing means

AssigneeNEC Corporation

InventorYasuharu Hidaka

Life of this patent

Estimating the term…

Loading patent…

Abstract

In a Bloch-line memory wherein a magnetic film comprises a first and a second major line and a minor loop portion defined between the first and second major lines, successive presence and absence of magnetic bubbles being transferred along the first major line in response to a plurality of information signals, the information signals being memorized as vertical Bloch line pairs in domain walls of stripe-domains generated in the minor loop portion, the memorized vertical Bloch line pairs being propagated towards the second major line and being read out as bubbles into the second major line, the magnetic film is formed with a plurality of endless long grooves at desired locations in the minor loop portion and an endless stripe-domain is generated and stabilized in each endless long groove, so that the propagation of vertical Bloch line pairs can be performed step by step. The magnetic film is further formed with a first and a second groove on both sides of the minor loop portion, and a first and a second connecting grooves to connect each endless groove to the first and second grooves on which the first and second major lines are disposed. The write-in operation and the read-out operation are performed by partially expanding the endless stripe-domain into corresponding one of the first and second connecting grooves and by carrying out the domain chopping technique therein.

Claims10

Dependent claims

In a Bloch-line memory device using a magnetic medium having a principal surface and an easy axis of magnetization orthogonal to said principal surface wherein at least one stripe-domain is generated in said magnetic medium and is surrounded by an outer domain wall in substantial parallel to said easy axis, a plurality of information signals being magnetically memorized in said domain wall as vertical Bloch line pairs, respectively, by write-in means, the memorized vertical Bloch line pairs being transferred in said domain wall by application of pulsed magnetic field in a direction orthogonal to said principal surface, and said memorized vertical Bloch line pairs being detected by detecting means to produce output signals representative of said information signals, respectively, the improvement which comprises:

at least one endless ring-like groove being formed in said principal surface of said magnetic medium to leave an island portion defined inside said endless groove so that said island portion is surrounded by an endless step portion formed at an inner boundary of said endless groove;
and
controllably generating means for controllably generating said stripe-domain in a form of an endless ring within said endless groove, said endless stripe-domain having an inner domain wall fixedly disposed under said endless step portion to thereby stabilize said endless stripe-domain, said endless stripe-domain being surrounded by an outer domain wall in which said vertical Bloch line pairs are written by said write-in means according to said information signals.

Dependencies are inferred from the claim text.