Western Digital Technologies, Inc.

Hgst Netherlands, B.v.

Yukimasa Okada

Xiaoyong Liu

Daniele Mauri

Takashi Wagatsuma

Katsumi Hoshino

Kouji Kataoka

Ji Li

Goncalo Baiao De Albuquerque

Ming Mao

Chih-Ching Hu

Goncalo Marcos Baião De Albuquerque

Guanxiong Li

Yung-Hung Wang

Takahiro Ibusuki

Changhe Shang

Ming Jiang

Zhanjie Li

Ying Hong

Yaguang Wei

Chen-jung Chien

Atsushi Kato

Anup Roy

Norihiro Okawa

Ichiro Oodake

Norihiro Ookawa

Hongxue Liu

Koji Kataoka

Xiaohai Xiang

Songzi Wang

The present disclosure generally relates to a dual free layer two dimensional magnetic recording read head. The read head comprises a lower shield, a first sensor disposed over the first lower shield, a first rear hard bias (RHB) structure recessed from a media facing surface (MFS), a first upper shield disposed over the first sensor, a middle shield disposed over the first sensor at the MFS, a second sensor disposed over the middle shield, a second RHB structure recessed from the MFS, and an upper shield disposed over the second sensor. The middle shield has a U-like shape and a ratio of a width to a throat height of 6:1, where the throat height is less than or equal to about 2 μm. The first and second RHB structures each individually has a stripe height about 3 times greater than a stripe height of the middle shield.

DFL TDMR middle shield throat height control for improved stability

A dual free layer (DFL) read head or reader oftentimes has a sidebump in a signal amplitude vs. cross-track profile plot. The sidebump is a magnetic signal of the reader in response to the magnetic field of magnetic media with finite thickness. The sidebump magnitude is far below the main magnetic signal of the reader and is offset from the center of the track in the cross-track direction. When two sidebumps are present (one on each side of the center of the track), the sidebump should generally and ideally be symmetrically offset in the cross-track direction else there is a negative impact on reader performance. To obtain offset symmetry, a synthetic antiferromagnetic (SAF) shield may be used, magnetic moments of soft bias layers can be adjusted, and spacing between the free layers of the DFL read head and the layers of the soft bias can also be adjusted.

DFL reader signal sidebump imbalance reduction

A two-dimensional magnetic recording (TDMR) read head includes a lower reader and an upper reader. Each of the lower reader and the upper reader may have a dual free layer (DFL) magnetic tunnel junction structure having first and second free layers located between lower and upper shields. A synthetic antiferromagnetic (SAF) structure is located on a side of each magnetic tunnel junction. A sidewall insulating layer is located between the lower soft bias layer of the SAF structure and the first free layer. The sidewall insulating layer can have a reduced height such that an upper soft bias layer of the SAF structure is in direct contact with a sidewall of the second free layer, or the upper portion of the sidewall insulating layer located between the upper soft bias layer of the SAF structure and the sidewall of the second free layer has a reduced thickness.

Dual free layer read head having recessed sidewall insulator layer and method of making thereof

The present disclosure generally relates to a read head of a data storage device. The read head includes a read sensor sandwiched between two shields. The shields can have different materials as well as a different number of layers. Furthermore the shields can be fabricated by different processes and have different heights and thicknesses. The ratio of the thickness to the height for the shields are substantially identical to ensure that the saturation field are substantially identical and balanced.

Read head sensor with balanced shield design

Aspects of the present disclosure generally relate to magnetic recording heads of magnetic recording devices. A read head includes a first reader, an insulating separation layer, and a second reader disposed above the insulating separation layer. The second reader includes a magnetic seed layer and a cap layer. The second reader includes a first upper free layer disposed between the magnetic seed layer and the cap layer, and a second upper free layer disposed between the first upper free layer and the cap layer. The second reader includes a barrier layer. In one implementation the second reader includes an antiferromagnetic (AFM) layer disposed between the magnetic seed layer and the insulating separation layer to pin the magnetic seed layer.

Magnetic read sensors having stabilized upper readers, and related methods

Aspects of the present disclosure generally relate to magnetic recording heads of magnetic recording devices. A magnetic read head includes a first pinning layer magnetically oriented in a first direction, and a second pinning layer formed above the first pinning layer and magnetically oriented in a second direction that is opposite of the first direction. The magnetic read head includes a rear hard bias disposed outwardly of one or more of the first pinning layer relative or the second pinning layer. The rear hard bias is magnetically oriented to generate a magnetic field in a bias direction. The bias direction points in the same direction as the first direction or the second direction. The magnetic read head does not include an antiferromagnetic (AFM) layer between a lower shield and an upper shield.

Magnetic read sensors and related methods having a rear hard bias and no AFM layer

The present disclosure generally related to a two dimensional magnetic recording (TDMR) read head having a magnetic tunnel junction (MTJ). Both the upper reader and the lower reader have a dual free layer (DFL) MTJ structure between two shields. A synthetic antiferromagnetic (SAF) soft bias structure bounds the MTJ, and a rear hard bias (RHB) structure is disposed behind the MTJ. The DFL MTJ decreases the distance between the upper and lower reader and hence, improves the area density capacity (ADC). Additionally, the SAF soft bias structures and the rear head bias structure cause the dual free layer MTJ to have a scissor state magnetic moment at the media facing surface (MFS).

Two-dimensional magnetic recording reader with dual free layer magnetic tunnel junction

The present disclosure generally relates to magnetic read heads comprising a dual free layer (DFL) structure. The magnetic read head comprises a first shield, a second shield, and a DFL structure disposed between the first and second shields. The DFL structure comprises a magnetic seed layer, a first free layer, and a second free layer. A non-magnetic spacer layer is disposed between and in contact with the first shield and the magnetic seed layer of the DFL structure at a media facing surface. A material and a thickness of the non-magnetic spacer layer is selected to control the coupling between the first shield and the magnetic seed layer of the DFL structure.

Dual free layer reader head with magnetic seed layer decoupled from shield

A hybrid read head structure for two-dimensional magnetic recording (TDMR) in a disk drive has two stacked current-perpendicular-to-the plane magnetoresistive (CPP-MR) read heads or sensors substantially aligned with one another in the along-the track direction to enable both sensors to read data from the same data track. The structure is a hybrid structure formed on the disk drive slider with the lower sensor being a dual free layer (DFL) or scissoring type of CPP-MR sensor and the upper sensor being a single free layer (SFL) type of CPP-MR sensor.

Two-dimensional magnetic recording (TDMR) read head structure with different stacked sensors and disk drive incorporating the structure

A magnetic read element having an additional magnetic layer, 'a floating magnetic shield', formed as a part of a capping structure of a magnetoresistive element. The capping structure is formed over the magnetic free layer and includes a magnetic layer that is located between first and second non-magnetic layers. The magnetic layer can advantageously be formed with a high magnetic permeability for increased signal amplitude and increased signal resolution. In addition, because the magnetic layer of the capping layer structure acts as a magnetic shield, it can reduce effective magnetic gap spacing for increased signal resolution.

Magnetic read head with floating trailing shield

A magnetic read sensor having an extended pinned layer and having a free layer structure with a back edge formed at an angle for optimizing sensor performance and pinned layer pinning. The magnetic free layer has a back edge that is formed at an angle of between 6 and 10 degrees relative to a plane parallel with the air bearing surface plane. The magnetic sensor can be formed by forming the free layer stripe height with an ion milling that is performed at an angle of 6 to 10 degrees relative to normal.

Magnetic sensor having optimal free layer back edge shape and extended pinned layer

In one embodiment, a magnetic disk device includes a magnetic disk medium, at least one magnetic head having at least one of: a magnetic read element configured to read data from the magnetic disk medium and a magnetic write element configured to write data to the magnetic disk medium, and a heating element configured to generate heat upon application of a voltage/current thereto, wherein the heating element is positioned on, near, or within the magnetic head, a drive mechanism for passing the magnetic disk medium over the at least one magnetic head, and a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head, wherein the controller is configured to retract the at least one magnetic head from a flying state above the magnetic disk medium and apply the voltage/current to the heating element while the magnetic head is retracted.

Error recovery based on applying current/voltage to a heating element of a magnetic head

In one embodiment, a magnetic head includes a lower shield, a read element positioned above the lower shield at a media-facing surface of the magnetic head, the read element having a free layer, an upper shield positioned above the read element, a first domain control layer having a direction of magnetization in a predetermined direction, the first domain control layer being configured to control a direction of magnetization of the free layer toward the predetermined direction, and a second domain control layer configured to have a magnetization in a same direction as the direction of magnetization of the first domain control layer, the second domain control layer being positioned above the first domain control layer, wherein the first domain control layer is a hard magnetic layer, and wherein the second domain control layer is a soft magnetic layer.

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Cupertino, CA, United States of America

Yukimasa Okada