Abstract: A memory includes a memory array, a sense amplifier, and a reference circuit. The memory array includes a memory cell. The sense amplifier includes a first terminal coupled to the memory cell and a second terminal. The reference circuit includes a first reference cell, a second reference cell, and a switch. The first reference cell has a first reference threshold voltage for providing a first reference current, based on a first reference word line voltage. The second reference cell has a second reference threshold voltage for providing a second reference current, based on a second reference word line voltage. The switch selectively provides one of the first and the second reference currents to the second terminal in response to a control signal. The first and the second reference word line voltages correspond to different voltage levels.

Abstract: A program control circuit and method thereof selectively controls a supply time of a word line bias voltage depending on the number of program cycles being in progress. Therefore, over-programming of MLCs can be prevented and an overall program time can be shortened.

Abstract: An apparatus and methods store data in a magnetic random access memory (MRAM) in a fast and efficient manner. Embodiments advantageously decrease the number of clock cycles required to store data by eliminating at least one wait state in a transition from a read state to a write state. Embodiments advantageously enhance the throughput of the MRAM and a related digital circuit, such as a computer system, which advantageously enhances the operating speed of the digital circuit.

Abstract: A program control circuit and method thereof selectively controls a supply time of a word line bias voltage depending on the number of program cycles being in progress. Therefore, over-programming of MLCs can be prevented and an overall program time can be shortened.

Abstract: In DRAM, a bit line pair are connected to the respective gates of an N channel MOS transistor pair of a read gate, and a write data line pair are connected to the respective gates of an N channel MOS transistor pair of a write gate. Therefore, since neither of the read data line pair and the write data line pair is directly connected to the bit line pair, no data signal on the bit line pair is destroyed by noise occurring on the read data line pair and the write data line pair.

Abstract: A magnetic domain device has at least one post element formed from a material that exhibits magnetic domain characteristics and that is positioned on a non-magnetic substrate material. A pair of electrical drive lines associated with a post element permit coincident current selection of the post element to reverse the direction of magnetization of the post element. This reversal is enhanced by one of the drive lines being configured to a slope portion of the post element so that this drive line is oriented to require a minimum field to reverse the magnetization direction of the post element.

Abstract: A close-packed magnetic bubble propagation device includes a pattern having a plurality of propagation elements positioned in at least four adjacent rows. These elements are spaced to provide a period or spacing of bubbles in these rows of less than three bubble diameters. Upon application of a rotating in-plane field to the elements, bubbles in adjacent rows move in opposite directions. A preferred embodiment of this propagation device has at least two storage loops which contain at least four adjacent horizontal rows of propagation elements. A preferred device utilizing this pattern has at least two storage loops and an access path which passes through each of the loops. An electrical conductor is associated with the propagation elements in the access path so that the passing of a current through the conductor together with the application of an in-plane rotating field to the elements causes bubbles associated with the elements in the access path to move along the access path.

Abstract: A device for storing digital information in the form of magnetic domains including at least two ferrimagnetic layers on a substrate. The ferrimagnetic layers are separated by a compensation wall and in the presence of a bias magnetic field single magnetic domains and superposed magnetic domain pairs, the superposed domains being separated by a compensation wall, are generated. All single and superposed domains are mutually repulsive. The domains within a superposed pair are attracted to each other. The generated domains are propagated to a shift register and when the reigster is filled a row of domains is coincidentally propagated, transversely out of the register, to a domain array region adjacent the register. Rows are then propagated through the array region to a second shift register where they are individually detected and annihilated. A control device assures the proper working relationship between all elements.

Abstract: A defect tolerant lattice file memory having means in the access column for annihilating lattice bubbles in a previously detected defective row thus eliminating an error in the digital information to be extracted from the lattice file. This annihilation means comprises a ladder formed in a conductor overlay located over the access column in which partial current loops may be formed by disconnecting certain selected portions of the ladder. These current loops create a localized magnetic field when the ladder conductor is activated thus annihilating the selected row of bubbles. Thus, lattice file chips found to have defective rows which will not support and maintain lattice bubbles in their desired coded state can now be utilized.

Abstract: A bubble storage system includes a closed loop propagation pattern suitable for use with a bubble lattice. The closed loop propagation pattern is folded and contains, for example, segments of a hexagonal lattice connected by 60.degree. turns to obtain a close pack bubble storage configuration. The bubbles are propagated along the pattern consisting, preferably, of C-bar or chevron type permalloy elements by a rotating magnetic field in the plane of the pattern. In a preferred embodiment, the folded closed loop propagation pattern is surrounded by a region of non-propagating bubbles retained by permalloy dot confinement means. There are substantially the same number of elements in the propagation pattern as there are bubbles in the lattice that are affected by the propagation elements.

Abstract: A bubble domain storage system is described which has the best features of contiguous element bubble propagation systems and bubble lattice file systems. An array of magnetic bubble domains, such as a lattice, is moved along contiguous propagation patterns in response to the reorientation of a magnetic field in the plane of the bubble domain film. Adjacent rows of bubble domains in the array move in opposite directions to provide individual storage loops within the array. Information accessing can be achieved by the use of input/output registers similar to those used in other contiguous disk bubble domain storage systems. For example, the storage system can be a conventional major/minor loop organization using contiguous element propagation patterns for the storage registers and for the input/output registers.

Abstract: A magnetic bubble device comprising a non-magnetic substrate layer, and a sequence of magnetic layers joined to each other and to the magnetic substrate layer, e.g. by epitaxial growing of crystalline layers, whereby at least two of the magnetic layers may accommodate magnetic bubbles which are stably joined through an interlayer magnetic compensation wall, or by an essentially finite potential barrier.

Abstract: In a display unit utilizing magnetic bubbles, selective extinction of the magnetic bubbles in a matrix results in a pattern of letters and/or images which are combinations of the magnetic bubbles as picture elements. The present display unit has in-plane anisotropic areas each of which has an easy magnetization axis parallel to the surface of the magnetic bubble material thin film produced by attaching the magnetically soft thin film on the magnetic bubble accommodation spaces in the magnetic bubble material thin film or by ion-implanting into the given spaces of the magnetic bubble material garnet. Therefore, according to this invention, the domain walls of the magnetic bubbles are attracted to said in-plane anisotropic areas and securely held at predetermined picture element positions.

Abstract: A magnetic bubble domain structure and method of making comprising a film of a nickel-iron alloy of 80 to 83.5% nickel content and substantially zero constant of magnetostriction formed by vapor deposition of the alloy onto a flat substrate at a substrate temperature in the range of room temperature to 200.degree. C. at an angle of incidence of approximately 60.degree. to a film thickness of 0.2.mu.m to 3.0.mu.m, the film being immersed in a magnetic field perpendicular to the film and of 1600 to 2400 oersteds intensity.

Abstract: A bubble lattice file has plural access channels, each access channel providing access to a bubble column aligned therewith for reading and/or writing in the aligned column. At least some of the access channels are spaced from a common reference by distances which for adjacent channels have substantially constant ratio, i.e., at least some adjacent access channels are spaced in a substantially geometric progression.

Abstract: A magnetic structure having a high magnetic bubble mobility which has the property that magnetic bubbles can be transported in it at very high velocities while using comparatively weak driving fields, comprising a substrate having a (110) oriented deposition surface on which a layer of rare earth -- iron garnet with a substitution of Mn.sup.3+ in iron lattice sites has been grown in compression in such a manner that the layer of rare earth-iron garnet has an orthorhombic anisotropy.

Abstract: A bubble lattice file comprising a plurality of propagate elements of magnetic film material positioned as an overlay over bubble supporting material with each element spaced from the bubble material such that a spacing gradient is formed between the element and the bubble material in the direction of the bubble propagation path. The elements comprising the main lattice memory file are arranged to support a hexagonal lattice of bubbles with one bubble propagation path in the form of rows and the other propagation path comprising accessing channels in the form of spaced apart columns.

Abstract: A structure and technique are provided for improving the average access time in a bubble lattice file (BLF) storage, and for providing reordering capability in the lattice file. The bubble lattice arrangement includes a translation structure for moving bubble domains in the lattice to various access channels where columns of bubble domains can be removed from the lattice. These are double access channels which remove two adjacent columns of bubble domains at the same time. A read means and a write means are associated with each channel of the double channel access for reading the information in each column removed from the lattice, and for writing new information into these columns. A transposition structure is provided for transposing the information represented by bubble domains in each of the removed columns, in response to a signal from associated control circuitry.

Abstract: Magnetic bubble domains are propagated in a magnetic medium in a desired direction using in-plane magnetic fields which are time varying but which have no spatial gradients. In applications such as information storage, the need for conventional propagation structures, such as offset conductor loops, patterned magnetic elements, and patterned ion implantation regions is reduced. Bubble domains having unwinding pairs of Bloch lines in their wall magnetization can be moved by applying appropriate in-plane magnetic fields, without the need for spatial gradients or variations in the magnetic field normal to the plane of the magnetic medium. The continuous movement of these bubble domains occurs by a cyclic process where the Bloch lines switch between two configurations, in an asymmetric way in response to the time varying in-plane field.

Abstract: Propagation of a lattice of magnetic bubble domains by field access techniques is achieved by using a periodic array of magnetic chevron elements. In response to the reorientation of a magnetic drive field in the plane of the chevron elements, magnetic poles are established to directly drive the lattice bubble domains. Those lattice domains not directly driven by magnetic poles are driven by repulsive forces within the lattice, such as those due to bubble-bubble interactions. The chevron arrays are designed to conform to the bubble lattice framework and patterns are established in which multiple bubble domains are associated with each chevron. The chevron elements can be symmetrical elements or skewed elements, and patterns are provided which can be used to drive multiple rows or columns of bubbles per chevron row or column. Generally, bubble domains alternate between being directly driven by magnetic poles along the chevrons and being indirectly driven by repulsive forces in the lattice.

Abstract: A photomagnetic image pickup element and system, the element comprising a thin film of magnetic material capable of having magnetic bubbles formed therein where the intensity of the magnetic-bubble collapse field varies with temperature; a first conductor pattern disposed on one side of the thin film; and a second conductor patterndisposed either on the one side or on the other side of the thin film, the first and second conductor patterns being so disposed with respect to one another as to form a lattice shape on the thin film.

Abstract: A magnetic device comprising a first and a second plate of a magnetic material between which domains are situated. An interaction force occurs between the domains in the two plates. Stable domain positions in a second plate define equally stable domain positions in a first plate. One or both plates can be provided with domain guiding structures. Domain displacement in one plate can control a domain displacement in the other so that a variation in the interaction force is produced.