Abstract: A lattice file using magnetic bubble domains which are arranged in a regular lattice which is moved or expanded to allow different operations, without requiring the need for bubble domains to be entered into or removed from the lattice. This distinguishes from prior lattice files where new information is entered into the lattice and information to be read is removed from the lattice. In a first embodiment, the inherent stability of the lattice is utilized by providing high density lattice for storage and a relaxed (expanded) lattice for operations such as read and write. Thus, the spacings between the elements in the lattice are changed but their relative positions in the lattice are not changed. In a second embodiment, the lattice is shifted without substantially changing the inter-element spacing and information is written and read from bubble domains magnetostatically coupled to the lattice domains.

Abstract: Apparatus is provided using as an integral portion thereof a confined array (such as a lattice) of interactive elements, the interactions among which are largely determinative of the positions of the interactive elements since there is a minimum of position determining structure for the elements within the area of confinement. Magnetic elements are suitable interactive elements, and in particular embodiments are shown using magnetic bubble domains. Structure is provided to form lattice arrays of interactive elements, to confine the lattice arrays, and to access elements outside and within the lattice array. In addition, various structures are provided to code the interactive elements for storage of information, and reading devices are provided to detect the information state of the interactive elements when these elements are coded. Various types of lattices and interactive elements can be used.

Abstract: A technique for accessing interactive elements, such as magnetic bubble domains, which are in confined arrays where the elements are located with respect to one another in accordance with interactions therebetween. In order to improve the access time to any element within the confined array, the elements are removed in a direction substantially transverse to the direction of their translational movement within the confined array. In particular, this technique is useful for accessing columns of magnetic bubble domains in a lattice array of bubble domains. A bubble pump device is utilized to remove the interactive elements from the array. The bias field conditions for this pump propagation structure are the same as for the lattice. Bubble domains can be removed from the lattice and returned to their positions within the lattice.

Abstract: Information processing is conveniently achieved by a structure which uses a novel binary switch. The switch can steer two data streams so that they will either cross one another or bypass one another, depending upon external control. A linear array of shift register loops are linked together by these flow-steering binary switches to form a storage structure which is termed a ladder. The ladder provides a variety of data structures. For example, it can alternate between LIFO (last in-first out) and FIFO (first in-first out). It can also dynamically rearrange data items according to recency of usage, in order to improve average access time to any data item. The binary switch and the ladder structure are conveniently provided using magnetic bubble domain technology, although other technologies can also be used.

Abstract: An improved thick film sensor for detection of magnetic bubble domains which can be configured to provide soft error detection and full data rate sensing. The sensor can be fabricated using single level masking techniques and is typically a magnetoresistive sensor comprised of NiFe. In its basic configuration, the sensor is comprised of two sets of magnetoresistive elements, each set including a sensor element and a dummy element, where both the sensor element and the dummy element provide a signal due to the bubble domain to be sensed. The magnetoresistive elements are arranged in a bridge circuit to give full data rate sensing and soft error detection. In a preferred embodiment, chevron expander-detectors are used, although the geometry of the sensor and dummy elements is not limited to chevron-type geometries.

Abstract: A rewritable bubble domain decoder employing a novel switch which is used to determine the path of magnetic bubble domains in a magnetic medium. In contrast to other decoders which are defined and unalterable by their structures, the present decoder has a universal structure, but is amenable to personalization and re-writing by re-loading personalizing (or control) bubbles. A basic element in the decoder is a switch which is characterized by its ability to have its normal function altered in addition to being able to switch between two states. That is, it is a switch in which the normal path direction for bubble domain movement can be changed at any time. In a preferred embodiment, the switch is comprised of a structure for holding a bubble domain which is used to route other bubble domains, together with a structure for overcoming the effect of the routing bubble domain on the input bubble domains to the switch.

Abstract: A nucleator for producing reverse magnetized domains in an amorphous magnetic material capable of supporting such domains. The nucleator is comprised of a current carrying conductor whose current carrying path includes a portion of the amorphous magnetic medium. The amount of current which flows through the conductor and through the amorphous medium is sufficient to nucleate magnetic domains therein. The nucleator can be fabricated as a portion of magnetic elements used to move bubble domains in an amorphous magnetic material and can be implemented using single level metallurgy. Thus, a current conducting nucleator is provided in which current flows through the bubble material itself.

Abstract: It has been discovered that magnetic bubble domains can be moved in a magnetic medium without requiring shaped structure along which magnetic poles are created for movement of the domains, and without reliance on magnetic fields established by conductor patterns. If a magnetic field is applied in the plane of the magnetic medium, bubble domains will be stretched in a direction parallel or anti-parallel to the field direction depending on the bubble domain polarity. If this magnetic field has an asymmetry in its amplitude versus time waveform, or if an asymmetry is created by a propagation element, bubble domains can be moved in the magnetic material. This discovery can be used to move bubble domains in a magnetic medium without requiring structure having a particular shape for domain movement, and without requiring conductors. Also, improvements can be made to existing propagation structures to make them more useful.

Abstract: A fabrication process for fabricating multiple layer magnetic bubble domain devices using only a single masking step. As a specific example, a thin conductor film (which could be a magnetic material, such as NiFe) is deposited on a substrate comprising a magnetic bubble domain material. This conductor film is coated with a resist which is exposed with an electron beam or an X-ray beam. The exposure density in a first area of the resist is different than that in a second area of the resist. Subsequent development of the resist will uncover the thin film only in the area which has received the greater exposure density. This area can then be used as a plating base for electro-plating another conductive layer, such as a thick gold film. Further development of the resist is used to uncover the second area (which initially received a lower exposure density).

Abstract: A bubble domain lattice system in which information exists as the presence and absence of bubble domains. A lattice exists in a conveyor layer and lattice bubble domains are coupled (magnetostatically or by exchange forces) to information bubble domains in another magnetic layer (information layer). These information bubble domains are coded in accordance with their presence or absence in the information layer. When the bubble lattice domains in the conveyor layer are moved, corresponding bubble domains in the information layer move in a similar manner, due to the magnetostatic coupling. Consequently, the high density advantages of a lattice arrangement are achieved in the present system, while coding of information is achieved without having to require different types of magnetic bubble domains.

Abstract: A magnetic bubble domain propagation device which is single sided and can be used to move bubble domains in amorphous magnetic films. The propagation structure is comprised of either one or two layers located on a single side of the amorphous magnetic medium. Preferably, the propagation elements in each layer are contiguous to one another to provide maximum density. In a preferred embodiment, the propagation elements are circular, but other geometries can be used. The amorphous magnetic material is deposited over these underlayer propagation elements in order to create a change in the profile of the amorphous material. This change in profile of the amorphous material acts as a restraining barrier to bubble domain movement, so that the bubble domains will move along the proper channel without drifting to other propagation channels, and will move from one propagation element to the next without merely idling at any of the propagation elements.

Abstract: Tunnel junctions are used to detect magnetic domains, such as bubble domains, using the change in Fermi level of one (or both) electrodes due to the magnetic field of the domain. The Fermi level shift causes the tunnel barrier height to change, leading to a change in tunneling conductance which is detectable as a current or voltage change. A simple tunnel junction in flux coupling proximity to the magnetic domains is suitable, but more sensitive detectors are made using Schottky barrier junctions, and magnetic semiconductors which exhibit conduction band splitting due to the stray field of the domains. In another embodiment, the magnetic sheet supporting the domains provides the tunnel barrier for sensing of the domains within it. Detection of submicron domains is easily achieved.

Abstract: A text editing system which is completely comprised of magnetic bubble domain components (or charge-coupled devices) is described. The essential parts of the system are a passive storage comprising a plurality of shift registers which are a convertible structure, i.e., they can be randomly accessed or sequentially accessed depending upon the state of a plurality of conversion switches. This provides great flexibility in entry, retrieval, and restoring. An active storage comprising a plurality of shift registers is used for various text editing functions, such as insertion of data, deletion of data, etc. In the active storage, an editing shift register is provided which implements the various text editing functions using techniques such as freezing data bits and bypassing data bits in order to change the order of the data and to close gaps which may occur in the data.

Abstract: A method for making a high density magnetic bubble domain system including the functions of read, write, storage, transfer, and annihilation. Only three masking steps are required, of which only one requires critical alignment. The proces makes use of the fact that magnetic disks can be placed on non ion implanted regions without adversely affecting the propagation properties of the implanted regions. Thus, the magnetic disks can be used to define ion implantation masks as well as for providing functions such as generation, propagation, reading, and annihilation. Magnetic elements for generation, storage and propagation, reading and annihilation are deposited in the same non-critical masking step, while all condutors used for writing, reading, and transfer are deposited by a single masking step requiring critical alignment.

Abstract: Apparatus using amorphous magnetic compositions having uniaxial anisotropy include bubble domain apparatus, light modulating apparatus, permanent magnet systems, and tape and disc information handling systems. The amorphous magnetic composition can be prepared in thin film or bulk form or as particles in a binder. The anisotropy can be parallel to the plane of a film of this material or perpendicular to the film plane. The amorphous material is comprised of a single element or is a multicomponent system where as at least one of the components has an unimpaired spin so that the composition has a net magnetic moment. The amorphous composition exists as a microcrystalline structure having localized atomic ordering over a distance 25-100 A, or as a substantially amorphous structure where localized atomic ordering is over distances less than 25A. Binary and ternary compositions, either alloys or compounds, are suitable.

Abstract: A method for making multilayer devices, such as magnetic bubble domain devices, which are comprised of a plurality of layers that are deposited using only a single critical masking step. A first metallic layer is deposited on a substrate including a magnetic bubble domain film, which may or may not have a nonmagnetic material thereon. A first resist layer is then applied, selectively exposed, and developed to expose at least two areas of the first metallic film. A thicker metallic layer is then deposited in the exposed areas, or is electroplated. After this, another resist layer is applied without deforming the pattern in the first layer, selectively exposed, and developed to protect certain areas of the thick metallic layer from subsequent formation of another metallic layer. During this subsequent formation, a second metallic film is formed using the first resist layer as a mask. After this, the resists are removed and the now uncovered portions of the original thin metallic layer are etched away.

Abstract: A text editing system is described which is comprised of single technology elements. That is, the system is comprised of dynamic shift registers which are entirely implemented with either magnetic bubble domain devices or charge coupled devices. These shift registers can be randomly accessed using write and read decoders to provide great flexibility in entry, retrieval, and restoring of data. An editing shift register is used for text editing functions, such as insertion of data, deletion of data, etc. This editing shift register performs the data manipulation functions by using techniques such as freezing of data bits and bypassing of data bits in order to change the order of the data and to close gaps which may occur in the data. The shift registers used for storage and the editing shift register are characterized in that all data manipulation functions and all accessing functions do not require a change in the sequence of the drive field used to move the data bits.

Abstract: A beam addressable file using as a storage medium an amorphous magnetic composition having uniaxial anisotropy. The storage medium can be prepared in thin film or bulk form or as particles in a binder. The storage medium can be comprised of a single element or a multicomponent system where at least one of the components has an unpaired spin so that the composition has a net magnetic moment. The storage comosition exists in a microcrystalline structure (i.e., it has localized atomic ordering over a distance 25-100 angstroms) and also in a substantially amorphous structure (i.e., when the composition has localized atomic ordering only over distances less than 25 angstroms). Binary and ternary compositions, either alloys or compounds, are suitable. particularly good examples are combinations of rare earth elements and transition metal elements.

Abstract: Bubble domain devices using conventionally known elements for providing a plurality of bubble domain functions, including writing, storage and reading, are provided using a magnetic medium of garnet structure characterized by the presence of a single rare earth ion present in all available dodecahedral lattice sites. These devices operate well over room temperature ranges. This material has sufficiently high anisotropy (of the order 10.sup.5 ergs/cm.sup.3) to support stable magnetic bubble domains in the material. The anisotropy is growth induced and cannot be explained by conventionally accepted theories of anisotropy in garnet bubble domain materials. In preferred embodiments, these rare earth iron garnet films are deposited on suitable substances, which can be any non-magnetic materials having suitable lattice constants to provide substantial lattice match with the magnetic garnet films. Examples are Eu.sub.3 Fe.sub.5 O.sub.12 on Nd.sub.3 Ga.sub.5 O.sub.12 or (Pr,Sm).sub.3 Ga.sub.5 O.sub.