Abstract: An arbitrary pattern write head assembly for writing timing-based servo patterns on magnetic storage media is provided, comprising: (a) a first pole piece comprising a substrate comprising a magnetic material, said substrate having a major surface; (b) a plurality of electrically conducting windings formed on the major surface; and (c) a second pole piece formed on the substrate, with a portion thereof formed above the plurality of electrically conducting windings and electrically insulated therefrom, the second pole piece having at least one opening therethrough defining a gap above the electrically conducting windings and the substrate, the second pole piece comprising at least two layers, each layer comprising a magnetic material. A method of batch fabricating servo writer heads is also provided for batch fabrication of servo writer heads at a very low cost. The method enables fabrication of heads capable of azimuthal recording commonly practiced in the video recording art.

Abstract: A magnetoresistive sensor design and fabrication process that provides improved microtrack profile linearity for servo elements while simultaneously providing stable and linear data sensing elements suitable for high density tape head applications. The stability and uniformity of both data and servo sensor elements is enhanced through the use of a grating profile under both the soft film biased magnetoresistive sensor layer and the hard bias stabilizing magnets. Processing steps are eliminated by replicating the grating pattern for the servo sensor elements through a thick layer of alumina or silicon dioxide. The outer read shield is removed from the servo elements using a stripping process that eliminates structural damage arising from alumina pinholes. Both element types are free of significant Barkhausen noise and instability because of the grating-stabilized domains in both the active magnetoresistive regions and the passive hard-biasing regions of each sensor.

Abstract: An interleaved bi-directional magnetic tape head for contact recording can have a poletip enhanced by providing a thin film of a soft magnetic material deposited onto a magnetic ferrite substrate. The second pole piece is a thin film of the soft magnetic material. A closure block of a non-magnetic ceramic encloses the layers together with leveling insulation layers and a deposited activating conductor turns. The stripe poletip deposited onto the magnetic ferrite extends for a distance just short of the first conductor turn and provides a balancing of the saturation moment of the pole pieces and provides for better recording capability, especially when operating in a trailing magnetic ferrite mode.

Abstract: An interleaved bi-directional magentic tape head for contact recording can have a poletip enhanced by providing a thin film of a soft magnetic material deposited onto a magnetic ferrite substrate. The second pole piece is a thin film of the soft magnetic material. A closure block of a non-magnetic ceramic encloses the layers together with leveling insulation layers and a deposited activating conductor turns. The stripe poletip deposited onto the magnetic ferrite extends for a distance just short of the first conductor turn and provides a balancing of the saturation moment of the pole pieces and provides for better recording capability, especially when operating in a trailing magnetic ferrite mode.

Abstract: A soft film biased magnetoresistive sensor (10) is fabricated to have reduced Barkhausen noise. The magnetic ratio of the film layers (14 and 18) is controlled to be in the range of 1.7 to 1.95 and the optimum bias point is controlled to be in the range of 35 and 41 degrees.

Abstract: Devices and circuits are described employing magnetoresistive materials exhibiting a negative .DELTA..rho. effect (.DELTA..rho.=.rho..parallel.-.rho..perp.). In these materials, the electrical resistivity .rho. of the material in a direction perpendicular to the direction of current through the material is greater than the electrical resistivity .rho..parallel. of the material in a direction parallel to the direction of the electrical current through the material. These are ferromagnetic materials exhibiting magnetoresistance in the presence of an electrical current through the material and a magnetic field applied to the material to magnetize it to saturation at room temperature. These devices and circuits have advantages over conventional devices and circuits employing magnetoresistive materials of the conventional type, in which .DELTA..rho. is a positive quantity.

Abstract: An alloy of Co.sub.x Pt.sub.y with y between 10 and 30 at. % is made by sputtering with H.sub.c >500 Oe and 4.pi.M.sub.s >5000 gauss, and zero magnetostriction. For 10 to 30 at. % Co the sputtered alloy has an H.sub.c of 500-1000 Oe with 4.pi.M.sub.s of 4000-14000 gauss, a magnetostriction passing through zero between 20 and 30 at. % of Pt. For thickness below 1000.ANG. H.sub.c is large (for the above range of alloys) and magnetization is also larger and coercivity varies as a direct function of Pt composition in the alloy up to 30 at. %.

Abstract: A low or zero magnetostriction ferromagnetic alloy is used for a magnetic recording medium. The alloy is (Fe.sub.y Co.sub.1-y).sub.1-x Cr.sub.x where y (Fe) is preferably 15-23 atomic percent of the FeCo part of the alloy. The value of x (Cr) is 7-20 atomic percent of the alloy and the remainder 1-x (FeCo) is 83-92 atomic percent of the alloy. The maximum ranges of the composition of the alloy are about as follows:Fe - 8-24 atomic percentCo - 56-83 atomic percentCr - 7-20 atomic percentThe material is adapted for use at room temperature below the Curie temperature of the specific alloy employed. When y (Fe) is 13 at. % and x (Cr) is 7 at. % the magnetostriction remains at zero, but the material is not corrosion resistant and thus it is useful for magnetic recording applications only where corrosion is not a problem. Thus the percentage of Cr must be within the range from 7-17 atomic percent.

Abstract: An amorphous alloy of cobalt and from about 14 to 30 atomic percent of titanium can be deposited upon a substrate by r.f. sputtering from 10 to 30 percent of titanium. The properties of the amrophous CoTi films are similar to those of transition metal-metalloid glasses in that they have soft magnetic properties (low H.sub.c) and their resistivity is in the 100-200 micro-ohm centimeter range. Unlike most metal-metalloid glasses, these films have very low magnetostriction and they are more stable to thermal annealing. They are more corrosion resistant than permalloy plated films. The films can be employed as magnetic yoke layers in magnetic recording heads or in the bubble propagation structures of bubble domain devices, as substitutes for 80:20 Ni:Fe alloys. The FeCoTi, NiCoTi and FeNiCoTi amorphous alloys have similar characteristics to the CoTi amorphous alloys for Ti concentrations on the order of 14 to 30 atomic percent where the ratio of Co to Fe and or Ni is greater than or equal to about 1 to 1.

Abstract: A sputtered thin film of an amorphous material composed of a magnetic transition metal X and element Y plus possibly an element Z has low coercivity for domains in the plane, has a well defined and stable magnetic easy axis which is extremely stable without heating above the Curie point, with a high and flat value of permeability from low frequencies to greater than 10 megahertz. Metal X can include at least one of Fe, Ni, and Co. Element Y can include at least one of Si and B. Element Z can be included composed of Cr, for example.

Abstract: A high power semiconductor device is formed by providing a semiconductor substrate of N.sup.- conductivity, rendering the backside of same porous as by subjecting same to anodic treatment carried out in a concentrated solution of hydrofluoric acid, converting the porous region to an N.sup.+ region, as by arsenic diffusion and forming an active device by conventional techniques in the top surface of the substrate. The method permits usage of high quality N.sup.- substrates and at the same time eliminates the requirement of growing thick epitaxial layers.

Abstract: A high power semiconductor device is formed by providing a semiconductor substrate of N.sup.- conductivity, rendering the backside of same porous as by subjecting same to anodic treatment carried out in a concentrated solution of hydrofluoric acid, converting the porous region to an N.sup.+ region, as by arsenic diffusion and forming an active device by conventional techniques in the top surface of the substrate. The method permits usage of high quality N.sup.- substrates and at the same time eliminates the requirement of growing thick epitaxial layers.