Abstract: A memory element has a sandwich structure in which rings of ferromagnetic material are spaced apart by a layer of a non-magnetic conductor (which is also typically a ring). These ferromagnetic rings will have differing magnetic hardness. At least one ring will be magnetically hard or antiferromagnetically-pinned. At least one other ring will be magnetically softer than the hard or antiferromagnetically-pinned ring. The non-magnetic conductor is at least thick enough to prevent essentially all exchange coupling between the ferromagnetic rings. Conducting leads provide current to pass through the ferromagnetic rings, perpendicular to magnetic moments in the ferromagnetic rings.

Abstract: A random access memory element utilizes giant magnetoresistance. The element includes at least one pair of ferromagnetic layers sandwiching a nonmagnetic conductive layer. At least one of the two ferromagnetic layers has a magnetic moment oriented within its own plane. The magnetic moment of at least the first ferromagnetic layer of the pair has its magnetic moment oriented within its own plane and is typically fixed in direction during use. The second ferromagnetic layer of the pair has a magnetic moment which has at least two preferred directions of orientation. These preferred directions of orientation may or may not reside within the plane of the second ferromagnetic layer. The bit of the memory element may be set by applying to the element a magnetic field which orients the magnetic moment of the second ferromagnetic layer in one or the other of these preferred orientations.

Abstract: A giant magnetoresistant displacement sensor includes at least one layered structure. This layered structure includes a harder magnetic (ferromagnetic or antiferromagnetic) layer having a fixed magnetic state, a second, softer, magnetic layer, and a metal layer interposed between and contacting these two layers to prevent exchange coupling between the two layers. The sensor also includes one or more indexing magnets for inducing a domain wall, at a measurand position, between regions of nonaligned magnetic fields in the softer magnetic layer; and an ohmmeter for measuring electrical resistance between points on opposite sides of the structure. In operation, the indexing magnets for inducing a domain wall are positioned relative to the giant magnetoresistant strip. The resistance across the strip is measured, and from this resistance measurement the position of the domain wall is determined.

Abstract: A magnetic memory element is fabricated from a thin magnetic film wherein the magnetic film is grown on a lattice-matched substrate and subsequently patterned to form a closure domain. The closure domain is comprised of a plurality of legs which are joined at domain walls. The individual legs are patterned in the thin magnetic film to lie parallel to an easy axis of the thin film crystal structure being used. Thus, each closure domain represents a magnetic memory element. Fringing fields about the memory elements are eliminated due to the closure domain design. An array of such closure domains can be grown on a substrate and can be packed to high densities up to the limits of current lithographic technology. Such thin film magnetic memory arrays are non-volatile and are compatible with existing RAMs.

Abstract: A semiconductor device useable as an electromagnetic isolator. The device has a semiconductor substrate epitaxial with a layer of metal, the latter deposited so as to generate a residual magnetic flux. A waveguiding structure is disposed transverse to the flux effective to cause electromagnetic signals propagating in the waveguiding structure to be attenuated a different amount depending on the direction of propagation. The waveguiding structure is preferably a seminconductor layer deposited epitaxially with the substrate in a channel in the metal.

Abstract: A passivating or insulating layer is described for semiconductor substrat The passivating layer is of the formula Zn.sub.1-x-y M.sub.x Q.sub.y Se:D where 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, M and Q represent different specified elements and D represents a dopant. It is prefered that M and Q are Fe or Mn. The substrate is preferably a III-V semiconductor compound. The devices are capable of rapid switching among other uses.

Abstract: A device and method for magnetizing a material having a magnetic constituent. In a preferred embodiment, a ferromagnetic film and a first film are selectively deposited at first and second locations on the material. The ferromagnetic film is magnetized in a first direction. A voltage source is coupled between the ferromagnetic and first films to enable a spin-polarized current to flow through the material to magnetize the material.

Abstract: A method of introducing magneto-optic bias into a ring laser permitting its se as a gyroscope. A Kerr reflective mirror is positioned in one leg of a triangle between reflectors at two vertices so that radiation from a reflector at one of the vertices is reflected at the maximum practical angle of incidence to a reflector at the adjacent vertex. By incorporating the reflective magneto-optic element at near-grazing incidence, full advantage is taken of the dependence of the magneto-optical properties upon angle of incidence.