Abstract: This invention relates to a magnetic memory including a first superconductor wire, a second superconductor wire disposed in such a manner as to cross the first superconductor wire substantially orthogonally, a first magnetic film disposed at the point of intersection between the first and second superconductor wires and a second magnetic film interposed between the first magnetic film and the first or second superconductor films, wherein at least one of the uniaxial magnetic anisotropy within the plane of the films and coercive force of the first and second magnetic films is mutually different. Furthermore, a superconductor film containing a large number of microscopic Josephson junctions is disposed between the first and second magnetic films or on the other side of the superconductor wire connected to the magnetic film, and a lead wire for applying a current is connected to the superconductor film.

Abstract: In a magnetic medium used in a Bloch-line memory device and having a first groove and a pair of second grooves deeper than the first groove with the first groove formed to leave a plateau extended on a principal surface in a predetermined direction between the second groove pair and having first and second end portions, a third groove is deeper than the first groove and has two portions spaced from the second end portion parallel and orthogonal to the predetermined direction. Adjacent to the second end portion, a primary conductor pair is formed on the first groove and adjacent to the second and the third grooves. Parallel to an easy axis of magnetization which is orthogonal to the principal surface, a magnetic domain is formed to surround the plateau by a bias magnetic field applied in a preselected direction parallel to the easy axis.

Abstract: A Bloch-line memory device comprises a magnetic medium including a read-out area and a potential barrier portion. The read-out area is on the principal surface of the magnetic medium and the potential barrier portion is located between the read-out area an a predetermined end portion of one or more domains. A pulsed magnetic field is strenghtened during a predetermined time interval to expand the magnetic domain towards the read-out area. When a magnetic domain with a single Block line at its end portion is expanded into the read-out area, the magnetic domain is chopped to produce a magnetic bubble. The magnetic bubble is detected by a detecting circuit and an output signal representative of an information signal is generated.

Abstract: A noble unit cell structure in a magnetic memory is disclosed, in which a ferromagnetic film is sandwiched between first and second wires at a cross-over area, and third and fourth wires are provided so as to sandwich the first wire. The third wire is contacted with the first wire so as to form a ring portion surrounding the ferromagnetic film and the second wire. The fourth wire is isolated from the first wire. At least the first, second and third wires are made of superconductive material. The ferromagnetic film has a uniaxial anisotropy along the second wire and its magnetization direction can be reversed by applying pulse currents to the second and fourth wires in an information writing process. In a reading process, the magnetization direction of the ferromagnetic film can be recognized by detecting either one of a superconductive state or a normal conductive state at the ring portion of the first and third wires.

Abstract: In a magnetic memory device for use in selectively carrying out a write-in operation and a readout operation of a pair of vertical Bloch lines as an information carrier in a domain wall of a stripe domain extended along a longitudinal direction, a deflected in-plane magnetic field is applied to an end portion of the stripe domain and deflected relative to the longitudinal direction at an angle within an angle range by the use of a pair of magnetic units. The deflected in-plane magnetic field serves to stably hold a single Bloch line to a predetermined flank wall of the stripe domain during the write-in operation or to stably separate three Bloch lines from one another during the readout operation. Such application of the deflected in-plane magnetic field also serves to smoothly propagate each Bloch line.

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.

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.