Tdk Corporation

Takumi Yanagisawa

Satoshi Miura

Kenzo Makino

Takahiko Machita

Takekazu Yamane

Naomichi Degawa

Takayasu Kanaya

Yoshikazu Sawada

Shohei Kawasaki

Kosuke Tanaka

Daisuke Miyauchi

Yosuke Antoku

Soji Koide

Minoru Ota

Yasushi Nishioka

Kenta Hamamoto

Naoki Ohta

Masashi Sano

Shunji Saruki

Keita Kawamori

Hideyuki Ukita

Shuji Okame

Masaru Hirose

A magnetoresistive effect element that prevents a recording medium from deteriorating by effectively inhibiting erroneous writing to a medium or the like includes a magnetoresistive effect part, and an upper shield layer and a lower shield layer that are laminated and formed in a manner sandwiching the magnetoresistive effect part from above and below, and is in a current perpendicular to plane (CPP) structure in which a sense current is applied in a lamination direction. The magnetoresistive effect part includes a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer that sandwich the nonmagnetic intermediate layer from above and below, the upper shield layer and the lower shield layer have inclined magnetization structures in which magnetizations of them are respectively inclined with respect to a track width direction, the magnetizations of the upper shield layer and the lower shield layer are mutually substantially orthogonal, the first ferromagnetic layer is indirectly magnetically coupled with the upper shield layer via a first exchange coupling function gap layer that is positioned between the first ferromagnetic layer and the upper shield layer, and the second ferromagnetic layer is indirectly magnetically coupled with the lower shield layer via a second exchange coupling function gap layer that is positioned between the second ferromagnetic layer and the lower shield layer.

CPP-type magnetoresistance effect element and magnetic disk device

A thin film magnetic head includes a spin valve film that includes a magnetization free layer, a magnetization pinned layer and a non-magnetic spacer layer that is disposed between the magnetization free and pinned layers, and a pair of side layers that are disposed at both sides of the spin valve film in a track width direction and at least in the vicinity of the magnetization free layer and the magnetization pinned layer. Each of the side layers has a bias magnetic field application layer that includes a soft magnetic layer and applies a bias magnetic field in the track width direction to the magnetization free layer, and a gap layer that is positioned between the spin valve film and the bias magnetic field application layer, and the side layers have compression stresses at least in the vicinity of the magnetization pinned layer.

Thin film magnetic head with side layers under compression stress

An MR element suppressing a false writing into a medium with an MR part has a CPP structure. The MR part includes a nonmagnetic intermediate layer and first and second ferromagnetic layers so as to interpose the nonmagnetic intermediate layer. First and second shield layers respectively have an inclining magnetization structure of which a magnetization is inclined with regard to a track width direction. The first and second ferromagnetic layers are respectively, magnetically coupled with the first and second shield layers. A magnetization direction adjustment layer for adjusting at least a magnetization direction of the first ferromagnetic layer is positioned at a rear end surface side of the first ferromagnetic layer, which is opposite to a front end surface receiving a magnetic field detected in the MR part.

CPP-type magnetoresistive element including a rear bias structure and lower shields with inclined magnetizations

The method according to the present invention includes the steps of: sequentially applying a plurality of different voltages to an MR element and sequentially detecting output signals from the MR element; and eliminating the MR element as a defective product when an evaluation value, based on a difference of SN ratios of the output signals from the MR element respectively obtained for each applied voltage, is less than a threshold value, and selecting the MR element as a non-defective product when the evaluation value is greater than or equal to the threshold value.

Method of manufacturing magnetoresistive element

The invention provides a method for fixing up the deterioration of a magneto-resistive effect device. A hard disk system is provided in it with a head heating means for heating a thin-film magnetic head, and by that head heating means, a defective site of the magneto-resistive effect device, which occurs as the hard disk system is in operation and is confined in a quasi-stable state, is fixed up in such a way as to return back to its own normal stable state. Thus, the deteriorated site of the magneto-resistive effect device (reproducing device) in the thin-film magnetic head, which is caused by the so-called thermal asperity as the hard disk system is in operation, is fixed up while it remains built in the hard disk system, i.e., without dismantling the hard disk system.

Method of repairing the deterioration of magneto-resistive effect device

A thin film magnetic head includes: a magneto resistance effect film of which electrical resistance varies corresponding to an external magnetic field; a pair of shields provided on both sides in a manner of sandwiching the MR film in a direction that is orthogonal to a film surface of the MR film; an anisotropy providing layer that provides exchange anisotropy to a first shield of the pair of shields in order to magnetize the first shield in a desired direction, and that is disposed on the opposite side from the MR film with respect to the first shield; and side shields that are disposed on both sides of the MR film in a track width direction and that include soft magnetic layers magnetically connected with the first shield.

Thin film magnetic head including soft layer magnetically connected with shield

A thin film magnetic head includes; an MR film that includes a pinned layer of which a magnetization direction is pinned, a free layer of which a magnetization direction varies, and a spacer that is disposed therebetween; a pair of shields that are disposed on both sides sandwiching the MR film in a direction orthogonal to a film surface of the MR film; and an anisotropy providing layer that provides anisotropy to a first shield so that the first shield is magnetized in a desired direction, and that is disposed on an opposite side from the MR film with respect to the first shield. The MR film includes a magnetic coupling layer that is disposed between the first shield and the free layer and that magnetically couples the first shield with the free layer.

Thin film magnetic head including spin-valve film with free layer magnetically connected with shield

A method of manufacturing a magnetic head, including a magneto resistance effect (MR) element that reads a magnetic recording medium, is disclosed. A multilayer film is formed on a shield layer. Unnecessary portions of the multilayer film are removed from both sides of the MR element in a first direction orthogonal to a lamination direction of the multilayer film and parallel to the MR element surface facing the magnetic recording medium. An insulating layer is formed on a surface exposed by removal of the unnecessary portions. An integrated soft magnetic layer covering both sides of the MR element in the first direction and an upper side of the MR element is formed, thereby configuring a second shield layer. An anisotropy application layer is formed on the second shield layer, thereby providing exchange anisotropy to the soft magnetic layer, and magnetizing the soft magnetic layer in a predetermined direction.

Method of manufacturing a magnetic head including shield layers which surround a MR element

A method for producing a thin film magnetic head including a magnetoresistive effect element (MR element) that has a magnetic sensor multi-layered film with a polygonal shape such that a vertex angle faces an air bearing surface (ABS) and a tip of the vertex angle is cut when the magnetic sensor multi-layered film is viewed from an X-Y plane that is parallel to a plane of a lower shield electrode layer includes a step for stopping a lapping process by using a measurement point in which a resistance value is steeply increased while the lapping face is gradually approaching the vertex angle of polygonal shape by lapping from the ABS side. Therefore, an excellent effect in which an ultra narrow track width that exceeds limits of photolithography technology can be securely and constantly formed is obtained.

Method for producing thin film magnetic head having magnetoresistive effect element

An MR element includes a lower shield layer, a magnetization free function part stacked on the lower shield layer, an upper shield layer stacked on the magnetization free function part, a nonmagnetic intermediate layer stacked on a surface, that is opposite to a magnetically sensitive surface, of the magnetization free function part, and a magnetization fixed function part stacked on the nonmagnetic intermediate layer. The nonmagnetic intermediate layer and the magnetization fixed function part are formed only within an outer region of the magnetization free function part, located opposite side to the magnetically sensitive surface.

Magnetoresistive effect element, thin-film magnetic head with magnetoresistive effect read head element, and magnetic disk drive apparatus with thin-film magnetic head

A reproducing method of reproducing magnetic information written in each of bits of a recording medium using a magnetic head having a reading element configured to measure external magnetic field intensity includes moving, measuring and specifying steps. In the moving step, the magnetic head moves to a position where the reading element covers two bits, one bit having known magnetic information, the other bit being adjacent to the one bit and having unknown magnetic information. In the measuring step, the reading element measures magnetic field intensity coming from the recording medium. In the specifying step, magnetic information of the bit having the unknown magnetic information is specified based on the magnetic field intensity measured in the measuring step and magnetic information of the bit having the known magnetic information.

Rework method and apparatus of magnetic record medium, information

A magnetic detector includes a magnetoresistive element and an impact sensor. The magnetoresistive element has a plurality of element-constituent layers that are stacked and include a free layer having a magnetization direction that changes in response to a magnetic field to be detected by the magnetic detector. The impact sensor has a plurality of sensor-constituent layers that are made of materials the same as those of the element-constituent layers and stacked in the same order as the element-constituent layers. The plurality of sensor-constituent layers include an impact detecting layer corresponding to the free layer and having a magnetization direction that changes by an inverse magnetostrictive effect in response to distortion created in the impact detecting layer by an impact received by the magnetic detector. The impact detecting layer exhibits a greater amount of change in magnetization direction when the magnetic detector receives an impact, compared with the free layer.

Magnetic detector including magnetoresistive element and impact sensor

A TMR element includes a lower magnetic layer, an upper magnetic layer, and a tunnel barrier layer of crystalline insulation material sandwiched between the lower magnetic layer and the upper magnetic layer. The lower magnetic layer includes a first magnetic layer and a second magnetic layer sandwiched between the first magnetic layer and the tunnel barrier layer. The second magnetic layer is formed from a magnetic material containing at least one of Fe, Co and Ni.

Tunnel magnetoresistive effect element having a tunnel barrier layer of a crystalline insulation material and manufacturing method of tunnel magnetoresistive effect element

The exchange coupled film according to the present invention comprises a buffer layer including a laminate in which an amorphous layer and a hafnium layer are laminated in that order, an antiferromagnetic layer laminated on the hafnium layer of the buffer layer via an intermediate layer with a thickness of at least 2 nm, and a pinned magnetic layer laminated on the antiferromagnetic layer.

Exchange coupled film including hafnium and amorphous layers usable in a magnetoresistive element in a thin-film magnetic head

A method for testing an MR element includes a step of obtaining a ferromagnetic resonance frequency fof the MR element to be tested by applying an external magnetic field in a track-width direction to the MR element, a step of calculating a stiffness magnetic field Hfrom the obtained ferromagnetic resonance frequency fusing a predetermined formula, a step of obtaining a relationship of a stiffness magnetic field Hwith respect to an external magnetic field applied in the track-width direction from the applied external magnetic field and the calculated stiffness magnetic field H, a step of obtaining a uniaxial anisotropic magnetic field Hof a free layer of the MR element from the obtained relationship of the stiffness magnetic field Hwith respect to the external magnetic field applied, and a step of judging whether the MR element is good product or not by comparing the obtained uniaxial anisotropic magnetic field Hwith a predetermined threshold.

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Tokyo, Japan

Takumi Yanagisawa