International Business Machines Corporation

Carnegie Mellon University

Seagate Technology Incorporated

Mars, Incorporated

Movid Information Technology, Inc.

General Electric Company

Other

Mark H Kryder

Han-Ping D Shieh

Sakhrat Khizroev

Dmitri Litvinov

Keith R Mountfield

Robert E Jones, Jr

George E Keefe

James A Bain

Javier I Guzman

Edward Charles Gage

Mitchell S Cohen

Hans Juergen Richter

Alina Deutsch

Terry Wayne McDaniel

Yeong S Lin

Elwood E Barnes

Rene Johannes Marinus Van De Veerdonk

Gary Clark Rauch

Clifton D Cullum, Jr

Katayun Barmak Vaziri

William H Meiklejohn

Efrem Y Huang

Steven D Granz

Xiaoyu Sui

Gregory W Beall

Walter Nystrom

Yingjian Chen

Yeong-Show Lin

Stanley H Charap

William C Cain

A stacked-thin-film structure that includes an Llo-ordered MnAl layer having high perpendicular magnetic anisotropy (PMA). In some embodiments, the Ll0-ordered MnAl layer has an Mn content in a range of about 35% to about 65%, a thickness less than about 50 nm, a saturation magnetization of about 100 emu/cm3 to about 600 emu/cm3 and a magnetocrystalline anisotropy of at least 1&#xd7;106 erg/cm. In some embodiments, the high-PMA Llo-ordered MnAl material is incorporated in magnetic tunneling junction stacked-film structures that are part of magnetoelectronic circuitry, such as spin-transfer-torque magnetoresistive random access memory circuitry and magnetic logic circuitry. In some embodiments, the high-PMA Llo-ordered MnAl material is incorporated into other devices, such as into read/write heads and/or recording media of hard-disk-drive devices.

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Iron-platinum (FePt) based magnetic recording media structures that provide small grain size and isolated-grain configurations suitable for high-density magnetic recording. In one of the structures, the recording media structure includes a thin film containing grains of L1FePt and boron as a segregant contained in intergranular regions located among the FePt grains. In another structure, the recording media structure includes a thin film containing grains of L1FePt, wherein the film is formed on an underlayer containing at least one material selected to control the size of the FePt grains in the film. Proper choices of materials, relative amounts of the materials, processing parameters, and other variables permit these structures to be formed with grain sizes, magnetization orientations, and perpendicular coercivities that allow designers to create magnetic storage devices having storage densities of 1 Tbit/inand greater.

Thin film media structure for perpendicular magnetic recording and storage devices made therewith

A magnetic recording medium comprises a magnetically soft underlayer having a plurality of cavities in a surface thereof, and a magnetic recording material in the cavities, wherein a surface of the magnetic recording material in the cavities is substantially coplanar with the surface of the soft underlayer. A recording system that includes the recording medium is also included.

Magnetic recording media with discrete tracks of magnetic material in a magnetically soft underlayer

A longitudinal recording head () for use with magnetic recording media includes a non-uniform gap () between first () and second magnetic () poles which focuses magnetic flux onto a small area of the magnetic recording medium. The non-uniform gap is preferably in the form of a cavity that is contoured to produce the desired flux pattern. Longitudinal recording heads incorporating the non-uniform gap are capable of improved recording densities.

Longitudinal magnetic recording heads with variable-length gaps

A perpendicular recording head for use with magnetic recording media includes a main pole having a concave tip. The concave tip focuses the magnetic flux from the main pole onto a smaller area of the magnetic recording medium than a conventional main pole when the main pole is at its flying height from the magnetic recording medium. Although the most preferred perpendicular recording head includes a concave cavity having an elliptical profile when viewed from the side, any substantially concave cavity may be used advantageously.

Perpendicular recording head including concave tip

The present invention provides perpendicular recording media having a soft magnetic underlayer and magnetic regions which generate an external magnetic field in the soft magnetic underlayer. The soft magnetic underlayer is brought into a substantially single-domain state by the magnetic field, thereby reducing or eliminating unwanted noise in the soft underlayer. In a preferred embodiment, the recording medium includes a ring-shaped soft magnetic underlayer positioned between concentric ring-shaped magnetic regions.

Perpendicular magnetic recording media with reduced-noise soft magnetic underlayer

A magnetic thin film includes a ferrite-containing underlayer and a ferrite-containing top layer. The composition of the underlayer differs from that of the top layer. During ex-situ annealing of the thin film structure, the underlayer inhibits diffusion of substrate atoms into the top layer. The composition of the underlayer relative to the top layer suppresses grain nucleation within the underlayer relative to the top layer at high temperatures and inhibits the nucleation of grains within the underlayer having undesirable composition, crystal structure, and orientation.

Magnetic thin film ferrite having a ferrite underlayer

Techniques for ultrahigh density writing on an erasable magnetic medium include using a micromachined mechanism having two probes for writing to the medium. Use of the two probe embodiment eliminates the need to change the magnetic orientation of the probe. In another embodiment, a single probe is provided which is heated to the vicinity of its Curie temperature to enable the magnetic orientation of the probe to be switched. The probe may be heated to its Curie temperature through the use of a heating element or a focused laser. In another embodiment of the present invention, either the magnetic orientation of the probe or the magnetic orientation of the medium may be switched through the combination of a static magnetic field, a radio frequency magnetic field and, under certain circumstances, the magnetic field of the probe. In all cases, the writing techniques enable information to be written to a magnetic medium in a manner which enables the information to be erased and the medium rewritten.

Techniques for ultrahigh density writing with a probe on erasable

A method of making c-axis perpendicularly oriented barium hexaferrite thin films by the crystallization of amorphous barium hexaferrite on a platinum underlayer is provided. Using a thin underlayer of platinum, barium hexaferrite films can be deposited by conventional rf diode or magnetron sputtering. Such deposition may be performed at room temperature, after which excellent c-axis perpendicular orientation can be achieved by rapid ex-situ annealing. The c-axis perpendicular orientation can also be achieved through in-situ annealing.

Method of enhancing the c-axis perpendicular orientation of barium

Methods and apparatus are provided for recording, erasing and reading elongated magnetic domains on magneto-optic media using laser energy. Recording and erasing can be carried out in the absence of a reversible external magnetic bias field. The preferred magneto-optic media to be used have compensation temperatures higher than about 40.degree. C. Recording and erasing are carried out using either continuously or intermittently energized lasers.

Direct overwrite magneto-optic system for strip erasing and recording

A new and improved unshielded horizontal magnetoresistive head is disclosed which utilizes multiple pairs of magnetoresistive elements. The present invention provides a device which is characterized by reduced output signal undershoot amplitudes, and an increased central peak pulse amplitude, while not significantly affecting the resolution of the device. The device is also characterized by increased signal to noise and signal to interference ratios. Magnetoresistive elements utilized in the device may be fabricated and/or manufactured by simplified processes, resulting in fabrication, manufacturing and cost benefits for the magnetoresistive head. Any number of additional magnetoresistive element pairs may be utilized dependent on the accuracy and resolution required by the specific application.

Unshielded magnetoresistive head with multiple pairs of sensing elements

An apparatus and method for detecting magnetic data on media is disclosed which utilizes an array or arrays of horizontal magnetoresistive sensors. The present invention detects the pitch or separation of magnetic transition data on the magnetic medium under test, and generates a signal that is independent of the velocity of the medium. In one embodiment, the magnetoresistive sensors employed in an array are spaced apart a distance which corresponds to the separation of magnetic transition data of interest, and the output of each sensor is connected to a voltage adder. The signal from the voltage adder is at a maximum when the separation of the magnetic transition data corresponds to the sensor separation. A comparator is connected to the output of the voltage adder, and compares the voltage adder output to a predetermined threshold voltage before indicating that a medium having a particular magnetic transition data pattern is detected. Alternate embodiments contemplate connecting linear circuitry, digital circuitry, fuzzy logic or other electronic circuitry to the array of magnetoresistive sensors. An apparatus according to the present invention is accurate, requires a minimum of parts, is simple and inexpensive to manufacture, and may be employed in a currency validator, magnetic card reader or the like.

Horizontal magnetoresistive head apparatus and method for detecting

Methods for directly over-writing the binary data value of a bit of digital data, stored in a particular one of a multiplicity of microscopic storage regions of a thin-film magneto-optic recording layer, in the absence of a substantial externally applied bias magnetic field, employ a magnetic material having a compensation temperature a few tens of degrees centigrade above room temperature. A source of energy is energized to heat the particular storage region to a sufficiently high temperature that the self-demagnetization field of the recording layer material inverts the net magnetic moment of that region. Multiple over-writing of the long-term stable stored data values can be provided.

Method and system for erasing previously recorded domains in a

An unshielded horizontal magnetoresistive head for magnetic sensing and reading devices. The horizontal unshielded magnetoresistive head is comprised of two magnetoresistive elements separated by a gap and a conductive cross member which electrically connects the magnetoresistive elements together and to a common electrical point such as system ground. A differential voltage sensing circuit is connected across the magnetoresistive elements for sensing voltage variations when magnetic data is sensed by the head. The present invention further facilitates a more simplified fabrication process which results in cost savings and more efficient fabrication methods and procedures.

Unshielded horizontal magnetoresistive head and method of fabricating

Method and system for overwriting binary data values in microscopic storage regions of a thin film ferrimagnetic layer without using external magnetic bias aiding the recording process. The ferrimagnetic layer is selected having a compensation temperature at least a few tens of degrees above room temperature. In recording data, any previously recorded data is erased to establish a known state and magnetic domains of reverse magnetic polarity are recorded when the known state differs from the binary data state by temporarily heating an area on the ferrimagnetic layer above the compensation temperature in the absence of any external aiding magnetic bias.

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Bradford Woods, PA, United States of America

Mark H Kryder