| 序号 | 专利名 | 申请号 | 申请日 | 公开（公告）号 | 公开（公告）日 | 发明人 |
|---|---|---|---|---|---|---|
| 81 | Method for fabricating a non-parallel magnetically biased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor element | US09920602 | 2001-08-02 | US20030039078A1 | 2003-02-27 | Min Li; Simon H. Liao |
| Within a method for forming a magnetoresistive (MR) sensor element there is first provided a substrate. There is then formed over the substrate a first magnetoresistive (MR) layer having formed contacting the first magnetoresistive (MR) layer a magnetically biased first magnetic bias layer biased in a first magnetic bias direction with a first magnetic bias field strength. There is also formed separated from the first magnetoresistive (MR) layer by a spacer layer a second magnetoresistive (MR) layer having formed contacting the second magnetoresistive (MR) layer a magnetically un-biased second magnetic bias layer. There is then biased through use of a first thermal annealing method employing a first thermal annealing temperature, a first thermal annealing exposure time and a first extrinsic magnetic bias field the magnetically un-biased second magnetic bias layer to form a magnetically biased second magnetic bias layer having a second magnetic bias field strength in a second magnetic bias direction non-parallel to the first magnetic bias direction while simultaneously partially demagnetizing the magnetically biased first magnetic bias layer to provide a partially demagnetized magnetically biased first magnetic bias layer having a partially demagnetized first magnetic bias field strength less than the first magnetic bias field strength. Finally, there is then annealed thermally through use of a second thermal annealing employing a second thermal annealing temperature and a second thermal annealing exposure time without a second magnetic bias field: (1) the partially demagnetized magnetically biased first magnetic bias layer layer to form a remagnetized partially demagnetized first magnetic bias layer having a remagnetized partially demagnetized first netic bias field strength greater than the partially demagnetized first magnetic bias field strength; and (2) the magnetically biased second magnetic bias layer to form a further magnetically biased second magnetic bias layer having a further magnetized second magnetic bias field strength greater than the second magnetic bias field strength. | ||||||
| 82 | Read head with file resettable dual spin valve sensor | US09369076 | 1999-08-05 | US06449134B1 | 2002-09-10 | Robert Stanley Beach; Matthew Carey; Bruce A. Gurney |
| A dual spin valve sensor is provided which is file resettable. An antiparallel (AP) coupled free layer structure is located between first and second pinned layer structures. The AP coupled free layer structure includes an AP coupling layer between first and second AP coupled free layers. When a current pulse is conducted through a sense current circuit the temperature of the sensor increases and conductive layers of the spin valve sensor exert current fields on the first and second pinned structures which set the magnetic spins of first and second antiferromagnetic pinning layers exchange coupled thereto. When the current pulse is terminated or reduced and the sensor cools the first and second pinning layers pin the magnetic moments of the first and second pinned layers antiparallel with respect to each other. Since magnetic moments of the first and second AP coupled free layers are also antiparallel with respect to each other the magnetic moments of the AP coupled free layer structure and the pinned layers are in phase so that a magnetoresistance, one on each side of the AP coupled free layer structure, are additive to provide a dual magnetoresistive effect. | ||||||
| 83 | Method for fabricating a non-parallel magnetically biased multiple magnetoresistive (MR) layer magnetoresistive (MR) sensor element | US09374310 | 1999-08-16 | US06295718B1 | 2001-10-02 | Min Li; Simon H. Liao |
| Within a method for forming a magnetoresistive (MR) sensor element there is first provided a substrate. There is then formed over the substrate a first magnetoresistive (MR) layer having formed contacting the first magnetoresistive (MR) layer a magnetically biased first magnetic bias layer biased in a first magnetic bias direction with a first magnetic bias field strength. There is also formed separated from the first magnetoresistive (MR) layer by a spacer layer a second magnetoresistive (MR) layer having formed contacting the second magnetoresistive (MR) layer a magnetically un-biased second magnetic bias layer. There is then biased through use of a first thermal annealing method employing a first thermal annealing temperature, a first thermal annealing exposure time and a first extrinsic magnetic bias field the magnetically un-biased second magnetic bias layer to form a magnetically biased second magnetic bias layer having a second magnetic bias field strength in a second magnetic bias direction non-parallel to the first magnetic bias direction while simultaneously partially demagnetizing the magnetically biased first magnetic bias layer to provide a partially demagnetized magnetically biased first magnetic bias layer having a partially demagnetized first magnetic bias field strength less than the first magnetic bias field strength. Finally, there is then annealed thermally through use of a second thermal annealing employing a second thermal annealing temperature and a second thermal annealing exposure time without a second magnetic bias field: (1) the partially demagnetized magnetically biased first magnetic bias layer to form a remagnetized partially demagnetized first magnetic bias layer having a remagnetized partially demagnetized first netic bias field strength greater than the partially demagnetized first magnetic bias field strength; and (2) the magnetically biased second magnetic bias layer to form a further magnetically biased second magnetic bias layer having a further magnetized second magnetic bias field strength greater than the second magnetic bias field strength. | ||||||
| 84 | Device comprising a first and a second ferromagnetic layer separated by a non-magnetic spacer layer | US09529524 | 2000-04-13 | US06252796B1 | 2001-06-26 | Kars-Michiel Hubert H. Lenssen; Hans Willem W. Van Kesteren |
| A sensor or a memory element comprises a fixed or free ferromagnetic layer. To increase the ease of writting the free layer (for memories) or the fixed layer (for sensors) the layer to be written or switched comprises multilayer configuration comprising two ferromagnetic sublayers separated by a non-magnetic spacer layer, the two ferromagnetic sublayers being magnetically coupled in such manner that their magnetization directions are anti-parallel and the device comprises means for directing a in-plane switching or re-setting current through the multilayered configuration, the current direction being transverse to the magnetization directions of the magnetically coupled sub-layers. | ||||||
| 85 | Magnetoresistance sensor having minimal hysteresis problems | US739632 | 1996-10-30 | US6166539A | 2000-12-26 | E. Dan Dahlberg; Timothy J. Moran |
| The present invention provides a method and apparatus for utilizing magnetoresistance devices for the measurement of weak magnetic fields. An oscillating excitation magnetic field is applied to a magnetoresistive (MR) sensing element such that the MR element is driven into one or both of two antiparallel saturation states. The amplitude of the excitation field is large enough to reverse the magnetization of the soft layer during each cycle. In one embodiment, the MR element is provided with a current, and a voltage proportional to the resistance is measured. Components of the voltage signal at multiples of the excitation frequency are then proportional to the environmental magnetic field. In one embodiment, an MR element having a resistance-versus-field transfer function that is symmetric (e.g., an anisotropic MR element) is used; while in another embodiment, an MR element having a resistance-versus-field transfer function that is asymmetric (e.g., a spin-valve MR element) is used. Various apparatus and methods for measuring the amount of time spent in one or both saturated states versus the unsaturated or transition states are described. In one embodiment, the magnetic excitation field is generated using a current strip deposited onto the top of the other device layers, so that the entire device can be produced on a single chip. In one embodiment, a "flexible" magnetoresistive structure includes a "flexible" ferromagnetic layer having a hard-magnetization-portion layer, and a soft-magnetization-portion layer, thus providing a smooth magnetic transition when this bilayer switches. One embodiment includes a supporting data-read head structure that positions the flexible magnetoresistive (MR) sensing element to sense a magnetic field in a data storage device such as a magnetic-disk drive. | ||||||
| 86 | Thin film magnetic head, magnetoresistance effect magnetic head and composite magnetic head | US987652 | 1997-12-09 | US5872691A | 1999-02-16 | Munekatsu Fukuyama; Yasuo Sasaki; Yutaka Soda; Koji Fukumoto; Tetsuo Sekiya |
| A thin-film magnetic head, a magnetoresistance effect magnetic head and an MR inductive head are disclosed. The thin-film magnetic head has one of thin-film magnetic cores stacked on a substrate and formed of two magnetic films and a non-magnetic film held between them, with a current flowing through the thin-film magnetic core in the direction of hard axis thereof. The magnetoresistance effect magnetic head has one of a pair of shield cores having a magnetoresistive element between them formed of two magnetic films and a non-magnetic film held between them, the magnetoresistive element being electrically connected to the shield core, with a sense current flowing through the shield core. The current flowing through the one shield core via the magnetoresistive element is preferably an AC of decrement amplitude for demagnetizing the shield core along with a DC sense current. Also, this current preferably flows in the direction of hard axis of the shield core so that magnetic properties of the shield core are stabilized or demagnetized by the magnetic field generated in the direction of easy axis. The MR inductive head has a second thin-film magnetic core as a common magnetic body of an MR head and an inductive head on one substrate, formed of two magnetic films and a non-magnetic film held between them, with a current flowing through the second thin-film magnetic core in the direction of hard axis thereof. | ||||||
| 87 | Spin-valve magnetoresistance sensor having minimal hysteresis problems | US655222 | 1996-06-05 | US5747997A | 1998-05-05 | E. Dan Dahlberg; Timothy J. Moran |
| The present invention provides a method and apparatus for utilizing spin valve magnetoresistance devices for the measurement of weak magnetic fields. The magnetoresistive element consists of a pinned ferromagnetic layer and a soft ferromagnetic layer separated by a thin spacer layer. The pinned layer may be pinned by high intrinsic coercivity, or by a neighboring antiferromagnet or high coercivity ferromagnet layer. An oscillating magnetic field is applied to the device. The amplitude of the excitation field is large enough to reverse the magnetization of the soft layer during each cycle, but small enough that the magnetization direction of the pinned layer is not much affected. In one embodiment, the applied field is applied using a current strip deposited onto the top of the other layers, so that the entire device can be produced on a single chip. | ||||||
| 88 | Method and apparatus for error recovery for unstable magnetorestrictive heads | US384309 | 1995-02-06 | US5661614A | 1997-08-26 | Albert John Wallash; Robert Eugene Eaton; Richard George Hirko |
| A method and apparatus is disclosed for recovering data with unstable low amplitude magnetorestrictive heads. After an error in data recovery is detected a technique is invoked that changes the bias current through the magnetoresistive head to the reverse direction in a predetermined manner. The method includes reversing the bias current direction, returning the bias current to its normal state and reading the data from the storage medium. Alternatively, the method includes reversing the bias current direction and reading the data when the bias current direction is reversed. | ||||||
| 89 | Magnetic head with magnetically stable shield layers and/or write poles | US473703 | 1995-06-07 | US5621592A | 1997-04-15 | Hardayal S. Gill; Tsann Lin |
| First and second shield layers of a read head are constructed of a lamination of NiMn and Fe-based layers to improve the performance of the shield layers when they are subjected to high external fields, such as from the pole tips of a write head combined therewith. Without lamination with one or more NiMn layers, many shield materials do not return to the same domain configuration after excitation from an external field. The result is that the Fe-based material assumes a different domain configuration after each excitation which changes the bias point of the MR sensor of the read head. By laminating with NiMn, the uniaxial anisotropy of the material can be increased to provide uniform domain configuration and exchange pinning between shield material NiMn returns the material to the same configuration after each external field excitation. The invention further provides fine tunings of the magnetic properties of the shield layer by various combinations of the Fe-based layers and/or the NiMn layer with NiFe layers. | ||||||
| 90 | Reset cassette with electromagnetic means for restoring the desired magnetization direction in a magnetoresistive head of a system for recording and/or reproducing signals | US240193 | 1994-05-09 | US5398146A | 1995-03-14 | Eeltje A. Draaisma |
| A system for recording and/or reproducing signals on a magnetic medium. The system comprises a tape cassette provided with a magnetic tape and an apparatus for cooperation with the tape cassette. The apparatus has a magnetic head comprising at least one magnetoresistive element having an easy axis of magnetization and a defined direction of magnetization extending at least substantially parallel to said axis. The system further comprises a reset cassette which can be loaded into the apparatus and which comprises a housing with a central opening for the passage of the magnetic tape and electronic means, arranged in the housing, for generating a non-alternating magnetic field at the location of the magnetic head when the reset cassette is present in the apparatus, which field has a direction similar to the defined direction of magnetization of the magnetoresistive element. | ||||||
| 91 | Structure of tape player/recorder magnetic head cleaner | US621964 | 1990-12-04 | US5113301A | 1992-05-12 | Ku-Di Huang |
| A tape player/recorder magnetic head cleaner, comprising two driving gear wheels respectively carried to rotate by the tape take-up reel and tape supply reel of the tape player/recorder; an endless belt mounted on said two driving gear wheels for synchronous motion; an elastic frame having a neck portion at the top for holding a cleaning head and two elongated slots longitudinally disposed at two opposite end for fastening the two eccentric columns made on said two driving gear wheels, permitting said cleaning head to be carried to alternatively move left and side while rubbing on the surface of the magnetic head. | ||||||
| 92 | Demagnetizing device having an oscillating permanent magnet | US71062 | 1987-10-09 | US4851945A | 1989-07-25 | Joseph F. Fritsch; Roxanne Y. Fritsch; Francois Malgat |
| A demagnetizing device for demagnetizing a sound head in a cassette tape recorder, comprises a cassette type housing. A carrier member pivotal in the housing carries a permanent magnet which oscillates with the carrier member sidewardly across an opening in the housing adjacent the sound head of the cassette tape recorder to demagnetize the sound head. A cam driven by a spindle of the cassette tape recorder acting on a follower drives the carrier member with oscillating movement. | ||||||
| 93 | Magnetic data transfer apparatus having a combined read/write head | US700642 | 1985-02-12 | US4651235A | 1987-03-17 | Tsutomu Morita; Shozo Toma; Yoshiaki Sakai |
| A magnetic disk drive is disclosed which has a write circuit for alternately exciting the a pair of coils of a read/write head in response to a two level write data signal when a write gate signal is in a prescribed state, thereby causing the coils to create magnetic fluxes in the opposite directions in the core. The write circuit excites a different one of the coils of the read/write head each time the write data signal changes in level from a predetermined one to the other. A final excitation circuit is provided for delaying, for example, the write gate signal for a preassigned length of time in order to cause the write circuit to excite a preselected one of the coils of the read/write head in a prescribed direction upon completion of the writing of the write data signal. Consequently, the residual magnetism of the read/write head is of one and the same orientation upon completion of writing, making possible the accurate detection of the peaks of the reproduced waveform at the time of subsequent reading. | ||||||
| 94 | Electromagnet for degaussing record-reproduce heads | US896776 | 1978-04-17 | US4183070A | 1980-01-08 | Motoyoshi Fujita |
| An electromagnet for degaussing a magnetic head and which includes a yoke having a gap and one or more coils wound thereon is characterized by the middle portion of the yoke face, at and adjacent to said gap, being wider than the magnetic tape that passes by the magnetic head, and by the side portions of said yoke face, away from said gap, being narrower than the tape. | ||||||
| 95 | Magnetic tape sensing head demagnetizer | US806416 | 1977-06-14 | US4086644A | 1978-04-25 | Richard C. Horian; James G. Horian |
| A magnetic tape sensing head demagnetizer disclosed has a housing with a hollow handle portion and a clear plastic probe portion projecting outwardly from the handle portion. A coil within the handle portion receives the inner end of a core which has an outer probe end that is received by the probe portion to protect it during demagnetizing of a tape sensing head as an AC voltage provides a pulsating flux to the core. A bulb received within the handle portion of the housing shines light through the probe portion thereof to provide illumination during the demagnetizing. Closing of a normally open switch energizes the coil with the AC voltage and concomitantly applies a portion of the voltage across the coil to the bulb to provide the illumination. An inner end of the probe portion is mounted by the handle portion with the probe end of the core located adjacent one lateral side edge of the probe portion and the bulb located adjacent the other side edge in a construction that gives the probe portion good light gathering and transmitting characteristics. Intensification of the transmitted light is achieved by tapering of the probe portion side edges toward each other in a direction toward the distal end of the probe portion. The handle portion of the housing has tapering side walls connected by a flat wall and a curved wall, all of which cooperate to facilitate handling of the demagnetizer and operation of the switch whose actuating button projects outwardly from the flat wall. | ||||||
| 96 | Tape pick-up head demagnetizer | US3655924D | 1970-12-01 | US3655924A | 1972-04-11 | PUSKAS ELEK |
| The pick-up head of a magnetic tape player is demagnetized by a moving, alternating magnetic field generated within the front end portion of a cartridge-type housing inserted into the player. The drive capstan of the player drives a carrier on which magnets are mounted to produce said alternating magnetic field. The carrier is reciprocated through a predetermined stroke relative to the pick-up head by an actuating mechanism.
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| 97 | Mechano-electric elimination of residual magnetization in a multi-track recorder utilizing a separate bias head | US35115064 | 1964-03-11 | US3369081A | 1968-02-13 | KATSUYA ATSUMI |
| 98 | Means for recording | US40589254 | 1954-01-25 | US2848555A | 1958-08-19 | MARVIN CAMRAS |
| 99 | Demagnetization system for magnetic recorder-reproducer | US22002351 | 1951-04-09 | US2682578A | 1954-06-29 | CLARAS CARL W |
| 100 | Demagnetizer for magnetic recorder-reproducer | US69412346 | 1946-08-30 | US2657277A | 1953-10-27 | BRASTAD WILLIAM A |
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