Hgst Netherlands, B.v.

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi, Ltd.

Hiroyuki Katada

Masato Shiimoto

Hiroyuki Hoshiya

Kenichi Meguro

Katsumi Hoshino

Jun Aoyama

Yasutaka Nishida

Nobuo Yoshida

Maki Maeda

Kazuhiro Nakamoto

Ikuya Tagawa

Takeshi Nakagawa

Satoru Okamoto

Masayoshi Shimizu

Kan Yasui

Katsuro Watanabe

Yoshiaki Kawato

Yo Sato

Kimitoshi Etoh

Junguo Xu

Mikito Sugiyama

Isao Nunokawa

Keiichi Nagasaka

Takayuki Ichihara

Naoto Ito

Masato Matsubara

Shun Tonooka

Koji Okazaki

Yosuke Urakami

Masahiko Hatatani

Shuuichi Kojima

Masato Yamashita

Miki Nishida

Tomoaki Hamasaki

You Sato

A magnetic media having a lateral exchange control layer formed on a magnetic oxide layer of a magnetic recording layer. A cap layer is formed over the lateral exchange control layer. The lateral exchange control layer can be an alloy comprising Co and one or more of W, Ru, Hf, Ta, Nb and Fe. The lateral exchange control layer has the highest magnetic saturation moment among all the recording layers, and increases spacing between magnetic grains (e.g. increased non-magnetic boundary width), thereby reducing lateral exchange sigma. The presence of lateral exchange control increases signal to noise ratio and reduces bit error rate and increases areal density.

Perpendicular magnetic recording media with lateral exchange control layer

Embodiments of the present invention generally include magnetoresistive heads, such as read heads, having a sensor structure and side shields disposed adjacent to the sensor structure. The distance between the side shields and the sensor structure increase in a direction from an ABS in the off-track direction. The magnetoresistive heads may include tapered surfaces on the side shields or sensor structure, or may include stepped surfaces on the side shields or sensor structure.

Graded side shield gap reader

A magnetic read head configured for two dimensional magnetic recording and having asymmetrical secondary read elements. The magnetic read head includes a primary read element configured to read a data track (i.e. n data track) and first and second secondary read elements located over adjacent data tracks (i.e. n+1, n&#x2212;1 data track) at either side of the data track to be read. The secondary read element have asymmetrical off track amplitude profiles, preferably such that they each have a steep amplitude profile at the outer side and a broader cross-track amplitude profile at their inner sides. This allows the secondary read elements to detect signals of the adjacent data track (so that those signals can be subtracted out of the signal from the primary reader) without the secondary read elements also picking up further adjacent data tracks (i.e. n+2, n&#x2212;2).

Two dimensional magnetic read head having asymmetrical secondary read elements

A hard-disk drive having a structurally efficient magnetic head slider utilizes a MAMR-based spin torque oscillator (STO) for head-disk contact detection and for flying height sensing. Contact detection and spacing estimation techniques consider the nominal temperature difference, and thus different criteria, between read and write operations.

Hard disk drive with contact detection using a spin torque oscillator

Embodiments of the present invention help to reduce mag-noise in a magnetoresistive head without deterioration in reproduced output and improve the signal/noise ratio (SNR) of the magnetoresistive head. According to one embodiment, the magnetoresistive head uses a synthetic ferri free layer and it is arranged such that the magnetic field which is applied to an end of a free layer with smaller film thickness and saturation magnetization in the track width direction by a coupling field is larger than the magnetic field which is applied to it by a bias layer.

Magnetic head using a synthetic ferri free structure

The embodiments disclosed generally relate to a read head sensor in a magnetic recording head. The read head sensor comprises side shields in addition to the upper and lower shields. The upper shield sensor is a multilayer structure with antiferromagnetic coupling. The side shield is a multilayer structure whereby a lower magnetic layer is separated from an upper magnetic layer. The upper magnetic layer is ferromagnetically coupled to a bottom layer of the upper shield. The bias direction of the read head sensor is antiparallel to the bottom layer of the upper shield.

AF-coupled dual side shield reader with AF-coupled USL

Approaches to improving the signal-to-noise ratio in a microwave-assisted magnetic recording hard disk drive over the entire region from the inner diameter to the outer diameter of the disk, especially in the context of shingled magnetic recording, include a narrower side gap on the side opposing a spin torque oscillator offset direction than the side gap in the offset direction, thereby increasing the gradient of the recording magnetic field in the cross-track direction and reducing the track edge noise of the recording pattern. Embodiments include use of a side shield on the side opposing the offset direction that has a higher saturation magnetization than the side shield on the side in the offset direction, thereby further increasing the gradient of the recording magnetic field in the cross-track direction.

Microwave-assisted magnetic recording head with high saturation magnetization material side shield

Embodiments described herein generally relate to a magnetic read head wherein read sensitivity distribution is made asymmetric in the off-track direction. The method of making the magnetic head is also disclosed. The read head may comprise a magneto-resistive effect element with an asymmetric structure around the element in the off-track direction and the read sensitivity profile in the off-track direction may also be asymmetric.

Asymmetric sensitivity reader

A microwave-assisted magnetic recording (MAMR) head according to one embodiment includes a main magnetic pole adapted to generate a writing magnetic field when current is applied to a write coil; a trailing shield positioned, at an air bearing surface (ABS), in a trailing direction from the main magnetic pole; and a field generation layer (FGL) positioned, at the ABS, between the main magnetic pole and the trailing shield, wherein either a portion of the main magnetic pole closer to the FGL or a portion of the trailing shield closer to the FGL is adapted to act as a spin polarization layer.

MAMR head adapted for high speed switching

Microwave-assisted magnetic recording head with asymmetric side gap for shingled magnetic recording

A magnetic disk drive system configured for shingled magnetic data recording wherein data tracks are recorded in an overlapping fashion on a magnetic media. The disk drive system includes magnetic write heads that are asymmetric so as to have increased writing at one side of the write head. The magnetic disk drive system includes magnetic write heads that are mirror images of one another so that write heads located at opposite surfaces of the magnetic media (e.g. one head facing up and one facing down) end up having preferential writing in the location relative to inner and outer diameters of the magnetic media.

Magnetic data recording system with mirror image asymmetric magnetic write elements

In one embodiment, a magnetic head includes a main magnetic pole, a trailing shield positioned on a trailing side of the main magnetic pole, a trailing gap positioned between the trailing shield and the main magnetic pole, side shields positioned on either side of the main magnetic pole in a cross-track direction, side gaps positioned between the side shields and the main magnetic pole on either side of the main magnetic pole in the cross-track direction, and trailing shield gaps positioned on either side of the main magnetic pole in the cross-track direction between the trailing shield and the side shields, wherein the trailing shield gaps extend beyond the side gaps in a direction parallel to the cross-track direction. In addition, a method for producing a magnetic head as described above is also disclosed, according to one embodiment.

Shield structure for reducing the magnetic induction rate of the trailing shield and systems thereof

In a conventional type magnetic head that performs microwave assisted recording, since a difference in a demagnetizing field between an end and the center of a field generation layer (FGL) grows larger when saturation magnetization of the FGL grows larger, the FGL that generates a microwave is not oscillated in a state of a single domain. Then, a spin-torque oscillator according to the present invention used for a magnetic head for microwave assisted recording is provided with at least one fixed layer, one non-magnetic intermediate layer and one alternating-current magnetic field generation layer respectively and is provided with a structure where saturation magnetization at ends of a film except an end in a direction from an air bearing surface to a surface opposite to it is made smaller than saturation magnetization in the center of the film of the alternating-current magnetic field generation layer.

Spin-torque oscillator for microwave assisted magnetic recording

A magnetic data storage system according to one embodiment includes a magnetic head adapted to record data according to a shingled magnetic recording (SMR) process. The magnetic head includes a main pole adapted to produce a writing magnetic field, a trailing shield positioned above a trailing side of the main pole, wherein a trailing gap is defined between the trailing shield and the main pole, and a spin torque oscillator (STO) positioned above a first trailing corner of the main pole at an STO-side of the main pole, wherein the trailing gap has a greater length in a film thickness direction near the STO-side of the main pole and a lesser length in the film thickness direction near a second trailing corner of the main pole opposite the first trailing corner in a track width direction of the main pole.

Microwave assisted magnetic recording (MAMR) head having an offset spin torque oscillator (STO) and narrow trailing gap

The present invention enhances reliability by correcting a write error due to unstable oscillation of a spin torque oscillator. In the present invention, a resistance value of a spin torque oscillator is monitored to detect that oscillation becomes unstable during recording. When a measured resistance value is out of a predefined normal range, information for which the recording operation is already performed is rewritten.

Growing community of inventors

Odawara, Japan

Hiroyuki Katada