Abstract: A magnetoresistive (MR) sensor having electrically conductive lead structures which are in electrical contact with the MR element at spaced positions. The lead structures comprise a thin film layer of body-centered-cubic tantalum which is separated from the MR element by a thin film seed layer formed of a material taken from the group consisting of TiW, TaW, Cr and W.

Abstract: A method for making a magnetic head slider comprising the steps of lapping the slider to form an air bearing surface, producing a chosen pattern of rails on the air bearing surface, and producing a chosen pattern of stress on the back side of the slider to remove the distortion produced in the slider by the lapping and rail formation steps. The stress pattern can be chosen to produce any desired range of crown and camber for the slider.

Abstract: A soft magnetic film includes a laminated structure having an alternating plurality of first magnetic and second magnetic film. The first magnetic films is of a predetermined thickness range and is made of a magnetic alloy of nickel, iron and nitrogen with the nitrogen present from greater than zero to 20 atomic percent. The second magnetic film is of a predetermined thickness range and is made of a magnetic alloy of iron and nitrogen with the nitrogen present from greater than zero to about 20 atomic percent. The films can be annealed in an applied magnetic field. The multilayer films have application as pole pieces and shields in magnetic heads. The magnetic heads are for use in dynamic storage systems including disk and tape media.

Abstract: Apparatus and method for communicating a call answered event and other communication services selection information to a call originating device (telephone). Tone signalling technology (DTMF) is used to indicate call progress. DTMF signals are generated by the switching system or associated telephony equipment.

Abstract: A magnetoresistive (MR) read transducer in which a layered structure comprising an MR layer, an antiferromagnetic material in direct contact with the MR layer and a thin layer of interdiffusion material in contact with the layer of antiferromagnetic material is subjected to a heating process to a temperature within a chosen temperature for a chosen time to form a magnetic interface between the antiferromagnetic material the MR layer. The magnetic interface produces a high level of exchange bias with the MR layer.

Abstract: A method and apparatus for detection of a timing data sequence and an end-of-preamble (EOP) flag based on a maximum-likelihood (ML) test performed on received data timing samples after synchronization has been achieved is described. The preamble preceding transmitted user data consists of a timing sequence followed by a known sequence of bits marking its end. After detection of synchronization, the receipt of the timing data sequence is recognized when an ML test detects no more than n.sub.V violations during a sequence of n.sub.l received samples. Similarly, the receipt of the EOP flag is recognized as soon as n.sub.F violations an ML test have occurred in the received sample sequence after recognition of the timing data sequence.

Abstract: A magnetoresistive (MR) read transducer has a thin film MR layer of ferromagnetic material and a nonmagnetic spacer layer in contact with the MR layer. The thin film spacer layer comprises an alloy of titanium (Ti) and tungsten (W) having a high resistivity. A thin film of soft magnetic material is deposited in contact with the nonmagnetic spacer layer so that the soft magnetic material is positioned parallel to, but spaced from, the MR layer. A feature of the invention is that the resistivity of the nonmagnetic spacer layer can be a specific value selected from a broad range of resistivity values by selecting the thickness, the Ti content, and/or the nitrogen content of the nonmagnetic spacer layer.

Abstract: A magnetoresistive (MR) sensor comprising a first and a second thin film layer of a magnetic material separated by a thin film layer of a non-magnetic metallic material. The first ferromagnetic layer is magnetically soft. The magnetization direction of the first layer of magnetic material is set substantially perpendicular to the magnetization of the second layer of magnetic material at zero applied field, and the magnetization direction of the second layer of magnetic material is fixed. A current flow is produced through the MR sensor, and the variations in voltage across the MR sensor are sensed due to changes in resistance of the MR sensor produced by rotation of the magnetization in the first layer of magnetic material as a function of the magnetic field being sensed. The variation of the resistance with the angle between the magnetizations of the first and second layers of magnetic material has been defined as the spin valve (SV) effect.

Abstract: A magnetic head slider having a protective coating on the rails thereof, the protective coating comprising a thin adhesion layer, a thin layer of amorphous hydrogenated carbon, and a thin masking layer. The protective coating is deposited on the air bearing surface of the slider after the thin film magnetic heads are lapped to a chosen dimension, but before the pattern of rails is produced on the air bearing surface. The protective coating protects the magnetic head during the rail fabrication process and in usage in a magnetic recording system protects the magnetic head from wear and corrosion damage.

Abstract: A magnetoresistive (MR) sensor comprising a layered structure formed on a substrate includes a first and a second thin film layer of magnetic material separated by a thin film layer of non-magnetic metallic material such as Cu, Au, or Ag, with at least one of the layers of ferromagnetic material formed of either cobalt or a cobalt alloy. The magnetization direction of the first ferromagnetic layer, at zero applied field, is set substantially perpendicular to the magnetization direction of the second ferromagnetic layer which is fixed in position. A current flow is produced through the sensor, and the variations in voltage across the MR sensor are sensed due to the changes in resistance produced by rotation of the magnetization in the front layer of ferromagnetic material as a function of the magnetic field being sensed.

Abstract: A magnetoresistive (MR) read transducer comprising an MR layer having longitudinally magnetized end regions separated by a central active region and a soft magnetic biasing layer parallel to but spaced from the MR layer. The easy axes of the MR layer and the soft magnetic biasing layer are tilted at a small angle with respect to the longitudinal axis of the transducer and these angles are substantially equal, but in the opposite sense.

Abstract: A rolling key for rolling up sleeping bags and the like is provided. A pair of tubular plastic rods are pivotally attached at one end, one of the rods being pivotally displaceable to a position parallel to and spaced from the other rod forming an open ended fork or key. A metal hook inserted through holes in the free ends of the rods fastens the free ends together and clamps a sleeping bag securely between the rods. In use the rolling key provides sufficient widthwise rigidity to easily roll the sleeping bag. A handle attached to attached end of the non-pivotable rod allows the rolled sleeping bag to tightly compress the rolled bag in a compact bedroll.

Abstract: A C-shaped clamp having elongated flanges at its ends defining the open portion of the "C". A bolt is inserted through holes provided in the flanges. A nut tightened on the bolt against one of the flanges compresses the C-shaped clamp. A U-shaped key slideably fitted in a lengthwise slot in the threaded end of the bolt engages the inside wall of one flange and the outwardly facing side of the nut and pulls the flanges apart when the nut is loosened on the bolt thus expanding the C-shaped clamp.

Abstract: A method whereby a low frequency, randomly varying magnetic field is generated by a device such that it interacts with the earth's geomagnetic field to eliminate rodents and similar pests both above and below ground which inhabit an area surrounding the device. The method is not limited to, but may comprise an electro-magnetic system that energizes and de-energizes one or more of a plurality of electric coils according to a predetermined sequence, thereby generating a specific low frequency magnetic field over a defined zone of influence. This magnetic field modulates and interacts with the earth's natural magnetic field (the geomagnetic field) thus inducing remanent defensive instinct responses in rodents and similar pests residing within the zone of influence. The effect, of the method, is to interfere with the pest's primitive survival and navigational instincts necessary for survival.

Abstract: A coaxial switch assembly includes a conventional reed switch (10) having a somewhat irregular enclosure (11) and protruding leads (20, 21). R.F. connectors (24, 25) are mounted at the ends of the leads, which are surrounded by predetermined lengths of dielectric tubular material (23). Electrically conductive flowable material (39) is injected within a surrounded shell (36) to fill the space remaining in a shell aperture (37) to rigidify the assembly and provide a continuous coaxial electrical conductor joining the outer body (27, 31) of the R.F. connectors to one another.

Abstract: A resonant frequency reciprocating print bar drive mechanism having print bar assembly mass 12 and counterweight 13 held in spaced relationship to each other by first and second leaf springs 16 and 17, which are of equal flexural stiffness. Drive solenoid 14 is mounted between the first and second springs 16 and 17, for inducing reciprocal oscillation between print bar 12 and counterweight 13. The print bar assembly, counterweight and spring assembly is itself suspended as a single unit from perimeter frame 11 by suspension springs 15. Suspension springs 15 have a much lower spring rate than that of leaf springs 16 and 17, and, as a result, the print bar assembly 12 and counterweight 13 will reciprocally oscillate, relative to each other, at a single resonant frequency.

Abstract: A low noise floor amplitude detector circuit utilizes a pair of semiconductor diodes connected between a radio frequency signal source and a terminating device that biases the diode at a conduction angle selected for maximum signal to noise ratio in the detector circuit. Optimum bias conditions and a low signal to noise ratio is achieved by using a conduction angle at each diode of 1.656 radians (approximately 67 degrees). This also results in matching of the radio frequency load impedance of the amplitude detector to the radio frequency impedance of a signal source.

Abstract: An assembly rigidly joining a pair of tubular members together includes one tubular member having a shaped slot formed in its side wall for receiving the open end of another tubular member. An eyebolt has an eye projecting at the center of the shaped slot and a threaded end projecting on the side wall opposite the shaped slot. The open end of the other tubular member is inserted into the shaped slot an a cross bolt which passes through apertures in the side wall near the open end engages the eye such that when a nut is tightened up on the threaded end of the eyebolt, the other tubular member is axially drawn into abutment with the one tubular member forming a rigid, mechanical joint between the two tubular members.

Abstract: Print enhancement circuitry to enhance the printed image produced by a laser beam printer is interposed between the character generator circuits and the laser drive circuits to modify the laser drive signals provided by the character generator circuits. Bit data representing successive lines of the bit map for a desired image are stored in a first-in first-out (FIFO) buffer. The bit pattern sample window having a central cell (bit) and a selected (arbitrary) number of neighboring bits is compared to a number of matching bit patterns or templates, each of which is associated with an error element or cell. When a logic matching network detects a match, a modification signal associated with a unique compensation cell (bit) is generated. The sample window central bit is then replaced (modified) with the unique compensation bit required by the matching template.

Abstract: A process for forming a dielectric patterned layer of any desired geometry on a selected substrate which includes vapor depositing selected reactants on said substrate only in areas thereon which are coextensive with the surface area of an adjacent metal electrode pattern.