Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Metals, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Yasuyuki Okada

Hiroyuki Hoshiya

Yoshiaki Kawato

Kuniaki Tabata

Koichi Okazawa

Toshiaki Tarui

Kazuhiro Nakamoto

Tetsuo Machida

Masafumi Mochizuki

Kazue Kudo

Susumu Tsuhara

Moriaki Fuyama

Gen Oikawa

Naoki Takada

Nobuo Yoshida

Kenichi Meguro

Katsumi Hoshino

Takashi Kawabe

Makoto Morijiri

Toshio Okochi

Yasunori Abe

Haruo Takeda

Hideya Akashi

Noriyuki Saiki

Toru Shonai

Chiharu Mitsumata

Hidefumi Iwami

Hiroaki Kambayashi

Yimin Hsu

Yohji Maruyama

Tomohiro Okada

Nian Xiang Sun

Yinshi Liu

Yunxiao Gao

Kyohei Aimuta

Yoshiaki Yamashita

Yoshiaki Eifuku

Kazunobu Mimura

Hiroyuki Kambara

A magnetic medium is magnetized in the relative movement direction at a predefined pitch km and a magnetic sensor includes plural magnetoresistive elements whose electrical resistance value changes depending on a magnetic field at a place where the magnetoresistive element is disposed. A position where the magnetoresistive element is disposed is defined as a reference position and, in addition to the magnetoresistive element of this reference position, the magnetoresistive elements as harmonic reducing patterns are disposed at the following positions, with P(n) defined as the n-th prime: a position offset by &#x3bb;m/(2&#xb7;P(n)) from the reference position toward at least one side of the relative movement direction, wherein N&#x2267;n&#x3e;1 and N is a natural number satisfying N&#x3e;3, and a position further offset by &#x3bb;m/(2&#xb7;P(L+1)) from a position offset by &#x3bb;m/(2&#xb7;P(L)), wherein 1&#x3c;L&#x3c;N.

Encoder

A rotation-angle-detecting apparatus comprising a magnet rotor, a magnetic sensor detecting the direction of magnetic flux from the magnet rotor, a correction circuit, and an angle-calculating circuit, the magnetic sensor having bridge circuits X and Y each comprising four connected magnetoresistive devices, each magnetoresistive device comprising a spin-valve, giant-magnetoresistive film, the correction circuit calculating difference (Vx&#x2212;Vy) and sum (Vx+Vy) from the output voltage Vx of the bridge circuit X and the output voltage Vy of the bridge circuit Y, and making their amplitudes equal to each other, and the angle-calculating circuit determining the rotation angle of the rotor by arctangent calculation from a signal (Vx&#x2212;Vy)' and a signal (Vx+Vy)&#x2032; supplied with the same amplitude from the correction circuit.

Rotation-angle-detecting apparatus

Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.

Thin film perpendicular magnetic recording head, their fabrication process and magnetic disk drive using it

A magnetic sensor comprising a bridge circuit in which four magnetoresistive devices are connected, the magnetoresistive device comprising a spin-valve, giant-magnetoresistive film comprising a pinned layer having unidirectional magnetic anisotropy, a free layer whose magnetization direction is rotated in alignment with an external magnetic field direction, and an intermediate layer sandwiched by the pinned layer and the free layer, and at least one of the magnetoresistive devices meeting the condition of 36&#xb0;&#x2266;&#x3b8;&#x3c;45&#xb0;, wherein &#x3b8; is an acute angle between its longitudinal direction and the magnetization direction of the pinned layer.

Magnetic sensor and rotation-angle-detecting apparatus with a bridge circuit

Embodiments in accordance with the present invention provide a Current Perpendicular to the Plane&#x2014;Giant Magnetoresistive (CPP-GMR) head exhibiting a high magnetoresistance (MR) ratio with a low area-resistance product. A lower shield is made up of a first shield layer/a crystalline reset layer/a second shield layer, and an amorphous material is used in at least a part of the crystalline reset layer, thereby controlling crystallinity of the second lower shield/the CPP-GMR head.

Magnetoresistive head and magnetic storage apparatus

A perpendicular write head includes a main pole comprising high moment magnetic layers laminated with both soft magnetic layers and non-magnetic layers for antiferromagnetic coupling (AFC) between the high moment material layers. The perpendicular write head includes a return pole connected to the main pole by a back gap closure at a distal end and separated from the main pole by a gap at an air bearing surface (ABS). A write coil is positioned between the main pole and the return pole and the surface area of the return pole at the ABS is substantially larger than the surface area of the main pole at the ABS.

Laminated high moment magnetic films antiferromagnetic coupling as write pole of perpendicular magnetic recording head

Embodiments of the invention implement a construction capable of reconciling high read output with high stability by improving the structures of magnetic films. In one embodiment, an inclined crystal grain structure is applied to a soft magnetic free layer, ferromagnetic pinned layer and so forth, thereby enhancing electron scatter performance of thin magnetic films.

Magnetic head having layered film with tilted crystalline grain structure

The disclosed invention provides a magnetic head of high stability in which 'erase after write' is prevented. Here is provided a magnetic head comprising a thin-film magnetic head for perpendicular magnetic recording, the thin-film magnetic head including a main pole with its tip facing a magnetic recording medium and coils for exciting the main pole, wherein the tip of or at least a part of the main pole consists of a soft magnetic multilayer containing laminations, each of which comprises a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film, wherein the antiparallel coupling layer causes antiferromagnetic interlayer coupling of the first ferromagnetic film and the second ferromagnetic film.

Magnetic head

The present invention provides a magnetic sensor suitable for high resolution and having high reliability by achieving stable output even at the occurrence of variations in a gap between a magnetic medium and the magnetic sensor, and a magnetic encoder using the magnetic sensor. The present invention uses a magnetoresistive element having magnetoresistive properties that satisfy the inequation, H10&#x2212;50&#x3c;H50&#x2212;90, where H10&#x2212;50 represents a magnetic field required for a resistance change from &#x394;R&#xd7;10% to &#x394;R&#xd7;50% with respect to a maximum amount of resistance change &#x394;R on a magnetoresitance effect curve, and H50&#x2212;90 represents a magnetic field required for a resistance change from &#x394;R&#xd7;50% to &#x394;R&#xd7;90%.

Magnetic encoder having a stable output property with unsaturated magnetic sensor

Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field exceeding 10 kOe while suppressing remanent magnetic fields occurring immediately after write operations. The perpendicular magnetic head comprises a main pole, a return path for supplying a magnetic flux to that main pole, and a conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer has a thickness within 0.5 to 5 nanometers, and The high saturation flux density layer has a thickness from 10 to 50.

A material for magnetic pole for attaining a writing head generating an intense recording magnetic field, and a structure and a manufacturing method therefor. The thin film magnetic head includes a magnetic pole layer having a plated magnetic layer containing Co, Ni and Fe formed on a plated underlayer of a sputtered magnetic layer containing Co, Ni and Fe. The CoNiFe magnetic layer having a composition: 40 wt %&#x2266;Co&#x2266;70 wt %, 10 wt %&#x2266;Ni&#x2266;25 wt % and 10 wt %&#x2266;Fe&#x2266;30 wt % and a peak intensity ratio in the X-ray diffraction of I(200)/I(111)&#x2267;0.5 and I(110)/I(111)&#x2267;1 (defining peak intensities for the face-centered cubic fcc (111) face, fcc (200) face and the body-centered cubic bcc (119) face as: I(111), I(200), I(110)).

Structure and plating method of thin film magnetic head and magnetic storage apparatus

A thin film magnetic head includes a lower magnetic pole, an upper magnetic pole provided so as to face the lower magnetic pole, and a magnetic gap layer provided between the lower magnetic pole and the upper magnetic pole. The upper magnetic pole constitutes a first magnetic layer formed on a side facing the magnetic gap layer by means of sputtering and a second magnetic layer formed on the first magnetic layer by means of plating, in which the saturation magnetic flux density of the first magnetic layer is set higher than that of the second magnetic layer. The thin film magnetic head composed as above is capable of generating a stronger magnetic field owing to its stably-formed magnetic core, thereby recording on a high-coercivity medium and high-density recording are made possible.

Thin film magnetic head and magnetic storage apparatus

Growing community of inventors

Odawara, Japan

Yasuyuki Okada