Hitachi, Ltd.

Hgst Netherlands, B.v.

Western Digital Technologies, Inc.

Hitachi Global Storage Technologies Netherlands B.v.

Shigeru Tadokoro

Takao Imagawa

Katsuro Watanabe

Shinji Narishige

Susumu Soeya

Hiroshi Kamio

Moriaki Fuyama

Takashi Kawabe

Wataru Kimura

Hideaki Tanaka

Hiroyuki Hoshiya

Yohji Maruyama

Kouichi Nishioka

Yoshihiro Hamakawa

Eiji Ashida

Yasunari Tajima

Akira Kumagai

Izuru Ishii

Hiroshi Fukui

Naoki Koyama

Tetsuo Kobayashi

Tadayuki Iwakura

Shuichi Kojima

Hiroaki Koyanagi

Saburo Suzuki

Akira Morinaga

Yukihiro Isono

Tetsuya Matsusaki

Masayuki Takagi

Sunao Yonekawa

Eiji Nakanishi

Kouji Okazaki

Masao Matsushita

The MAMR head comprises a main pole, a spin torque oscillator (STO) positioned over the main pole, and write coils coupled to the main pole. The STO generates a high frequency magnetic field on a magnetic medium. The controller is configured to supply the STO with first bias current at a first bias current level, and further supply the STO with second bias current at a second bias current level. The controller is further configured to time the second bias current to coincide with an electrical current overshoot in the write coils.

STO bias control for MAMR head reliability

Embodiments disclosed herein generally relate to a perpendicular magnetic recording head for recording magnetic information and a magnetic recording device employing the magnetic head. The magnetic recording head comprises at least one thin shield region having a high coercive force and a magnetization direction oriented towards the right when viewed from the MFS with the leading side on bottom and the trailing side on top, and at least one thick shield region having a low coercive force. The thin shield region surrounds a main pole, and the thick shield region partially surrounds the thin shield region. The magnetic recording head is able to reduce FTI by controlling the magnetization direction of the shield layers.

Perpendicular magnetic write head having a controlled magnetization state shield

A magnetic recording write head has a continuous electrically conductive plate with an aperture, a coil region around the aperture and heat-sink regions spaced from the coil region. A yoke stud is located in the aperture and connects the upper yoke layer to the main pole. The plate with the aperture replaces the multi-turn coil of the prior art and thus allows for a short yoke height. Write current is directed to the plate coil region and induces a magnetic field in the aperture, which generates magnetic flux in the yoke stud and the connected main pole. The heat-sink regions dissipate heat generated in the plate by the write current. A lower electrical lead layer is located below the plate and also has an aperture coincident with the aperture in the plate and a coil region around the aperture to assist in generating the magnetic field in the aperture.

Perpendicular magnetic recording write head with plate having coil regions and heat-sink regions

Even if the track and gap widths are made narrow in a read head, a narrow track head has so far been unable to afford satisfactory off-track characteristics because of a wide shield spacing over electrodes. The invention provides a magnetic head wherein, in the height direction of a magnetoresistive element, the spacing between an upper magnetic shield and a lower magnetic shield at an air bearing surface is narrower than the spacing between the upper and lower magnetic shields formed over a thickest portion of each of electrodes in contact with associated magnetic domain control layers.

Magnetic head with a narrow spacing between magnetic shields at air bearing surface

Protrusion of head elements to an air bearing surface is effectively reduced and their contact with a recording medium is thereby prevented by forming a level gap (concave) of about 3 nm in a multilayered protective film on the air bearing surface in a part matching an inductive write thin film head in a recording/reproducing separated type magnetic head and thereby offsetting protrusion of the head elements to the air bearing surface due to thermal deformation of the heads.

Recording/reproducing separated magnetic head with concave portion formed in air bearing protective film

A tunnel junction MR head can be easily manufactured and arranged as follow. A first tunnel junction is formed by a magnetization free layer, a first magnetization pinned layer and a thin insulated layer formed between the both layers. A second tunnel junction is formed by the magnetization free layer, a second magnetization pinned layer and an insulated layer. The first and second tunnel junctions are connected to both ends of the magnetization free layer through the magnetization free layer. A detection current flowing from a first electrode connected to the first tunnel junction is passed to a second electrode through the first tunnel junction, the magnetization free layer and the second tunnel junction.

Magnetic tunnel junction magnetoresistive head

A magnetoresistive head in which Barkhausen noise is substantially suppressed and a variation in reproduction is minimized, and a magnetic disk apparatus using the same magnetic head have been provided. The feature of the magnetic head and the magnetic disk apparatus of the invention resides in the provision of the longitudinal bias layer which comprises a hard magnetic thin film formed on an underlayer made of either of a ferromagnetic thin film having a body-centered cubic lattice crystal structure formed of body-centered cells, an amorphous ferromagnetic thin film or antiferromagnetic thin film having a body-centered cubic lattice crystal structure formed of body-centered cells.

Magnetoresistive head and magnetic disk apparatus

A magnetoresistive head in which Barkhausen noise is substantially suppressed and a variation in reproduction is minimized, and a magnetic disk apparatus using the same magnetic head have been provided. The feature of the magnetic head and the magnetic disk apparatus of the invention resides in the provision of a longitudinal bias layer which comprises a hard magnetic thin film formed on an underlayer made of either a ferromagnetic thin film having a body-centered cubic lattice crystal structure, or an amorphous ferromagnetic thin film or antiferromagnetic thin film having a body-centered cubic lattice crystal structure.

A magnetic head of storage/read separation type in which both a reproducing head of magnetoresistive type and a write head of magnetic induction type are formed through a magnetic shield. The magnetic head includes a ferromagnetic material and an antiferromagnetic material in intimate contact with said ferromagnetic material. At least a part of the antiferromagnetic material acts to bring about unidirectional anisotropy in the ferromagnetic material, and is made of Cr--Mn-based alloy, and at least a part of the ferromagnetic material in intimate contact with the antiferromagnetic material is made of Co or Co-based alloy.

Magnetic layered material, and magnetic sensor and magnetic storage/read

A magnetoresistive head comprising a magnetoresistive film having electric resistance varying with a magnetic field, a pair of electrodes for causing a current to flow into the magnetoresistive film, and a soft magnetic film for applying a transverse biasing field to the magnetoresistive film, the soft magnetic film containing at least one material of iron, cobalt, and nickel, and at least one compound of zirconium oxide, aluminum oxide, hafnium oxide, titanium oxide, beryllium oxide, magnesium oxide, a rare earth oxygen compound, zirconium nitride, hafnium nitride, aluminum nitride, titanium nitride, beryllium nitride, magnesium nitride, silicon nitride, and a rare earth nitrogen compound. The electric resistance of the soft magnetic film is raised by adding a compound thereto and current diverted from the magnetoresistive film to the soft magnetic film decreases, so that the reproducing voltage of the magnetoresistive head rises.

Magnetoresistive head and manufacturing method therefor

A magnetic head having a magnetoresistive head having a spin valve structure in which a composite magnetic layer of a rotatable magnetizing direction layer and oxide or the like is used for a lower shielding layer and/or an upper shielding layer and a magnetic disk apparatus using such a head are disclosed. According to the invention, a magnetic head having a head of a magnetoresistance effect type generating a high output with low noises and a magnetic disk apparatus having a large quantity with high recording density can be realized.

Magnetic head and magnetic disk apparatus provided therewith

A magnetic laminated film used for a magnetic transducer is constructed in such a way that a ferromagnetic film as a ferromagnetic body is made of, for example, a Ni--Fe alloy film, formed on a substrate made of, for example, glass, and an antiferromagnetic film as an antiferromagnetic body having crystal structure of body-centered cubic lattice, for example, made of a Cr alloy film is laminated on the top layer. Further, a magnetic transducer using the magnetic laminated film is applied to a magnetic head in a magnetic recording device in accordance with the present invention.

Magnetic transducer and magnetic recording device utilizing material in

A ferromagnetic and antiferromagnetic material having a high exchange coupling and a high thermal stability, and a magnetic storage system using this material which has excellent reliability and recording density, and a magnetoresistive storage/read separation head having a high sensitivity and a low noise property. The magnetic storage/read system of the invention mounts a magnetoresistive head using a chromium-manganese antiferromagnetic layer/a cobalt alloy layer as a pinning layer or the longitudinal bias layer of the spin-valve type magnetoresistive layered film.

A magnetic disc apparatus capable of noiseless, high-output reproduction is disclosed. A magnetic head including a magnetic domain control structure having an antiferromagnetic film for applying a longitudinally biasing magnetic field to a magneto-sensitive portion of a magneto-resistance effect film, and a magnetic film smaller in spontaneous magnetization than the magneto-resistance effect film, which magnetic film is interposed between the magneto-resistance effect film and the antiferromagnetic film. A magnetic disc apparatus is thus realized which is high in recording density and usable in stable manner within the operating temperature range.

Growing community of inventors

Odawara, Japan

Shigeru Tadokoro