Read Rite Corporation

Western Digital (fremont), Inc.

Ningjia Zhu

Yiming Huai

Wenjie Chen

Yingjian Chen

Mahendra Pakala

Jing Zhang

Kyusik Sin

Fuminori Hikami

Amritpal Singh Rana

Peter I Bonyhard

Geoff Anderson

Ernest Anthony Louis

Geoffrey Anderson

Magnetoresistive (MR) sensors are disclosed having mechanisms for reducing edge effects such as Barkhausen noise. The sensors include a pinned layer and a free layer with an exchange coupling layer adjoining the free layer, and a ferromagnetic layer having a fixed magnetic moment adjoining the exchange coupling layer. The exchange coupling layer and ferromagnetic layer form a synthetic antiferromagnetic structure with part of the free layer, providing bias that reduces magnetic instabilities at edges of the free layer. Such synthetic antiferromagnetic structures can provide a stronger bias than conventional antiferromagnetic layers, as well as a more exactly defined track width than conventional hard magnetic bias layers. The synthetic antiferromagnetic structures can also provide protection for the free layer during processing, in contrast with the trimming of conventional antiferromagnetic layers that exposes if not removes part of the free layer.

Spin valve sensors having synthetic antiferromagnet for longitudinal bias

A method and system for providing a magnetoresistive sensor is disclosed. The method and system include providing a first pinned layer, providing a free layer having a length, and providing a first spacer layer disposed between the first pinned layer and the free layer. The first spacer layer has a first interface with the first pinned layer. The method and system also include providing a second pinned layer and providing a second spacer layer disposed between the free layer and the second pinned layer. The second spacer layer has a second interface with the second pinned layer. A direction of a current passed through the magnetoresistive sensor is through the first interface, through the second interface, and along at least a portion of the length of the free layer.

Method and system for providing a dual spin filter

A method and system for providing a magnetoresistive head that reads data from a recording media is disclosed. The method and system include providing a first shield, a second shield, a magnetoresistive sensor, and a lead. The first shield has a first end, a central portion and a second end. The first end is closer to the recording media during use than the second end. The second shield has a first end, a central portion, and a second end. The first end of the second shield is separated from the first end of the first shield by a read gap. The central portion of the second shield is separated from the central portion of the first shield by a distance that is greater than the read gap. The magnetoresistive sensor is disposed between the first shield and the second shield and has a front end and a back end. The front end of the magnetoresistive sensor is electrically coupled with the first end of the first shield or the first end of the second shield. The lead is electrically coupled with the back end of the magnetoresistive sensor. Thus, current is driven through the magnetoresistive sensor in a direction substantially perpendicular to the recording media during use.

Vertical giant magnetoresistance sensor using a recessed shield

A method and system for providing a spin valve for use in a magnetoresistive head is disclosed. The method and system include providing a synthetic pinned layer, a nonmagnetic spacer layer, and a free layer. The free layer has a first magnetization canted from a first direction by a first angle. The nonmagnetic spacer layer is disposed between the free layer and the synthetic pinned layer. The synthetic pinned layer has a second magnetization in a second direction. The second direction is canted from a third direction that is transverse to the first direction by a second angle. The second magnetization is substantially orthogonal to the first magnetization.

Method and system for reducing assymetry in a spin valve having a synthetic pinned layer

A hybrid dual spin valve sensor includes a standard spin valve sharing a common free layer with a synthetic spin valve. The standard spin valve consists of a first antiferromagnetic layer having a first blocking temperature, a first soft ferromagnetic layer, a first spacer layer, and the common free layer. The synthetic spin valve consists of the common free layer, a second spacer, a second soft ferromagnetic layer, a third spacer layer, a third soft ferromagnetic layer, and a second antiferromagnetic layer having a second blocking temperature. Each of the two antiferromagnetic layers has a fixed magnetization orientation antiparallel to the other. A lead set configured to pass a sensing current from a current source through the hybrid dual spin valve, and a sensing circuit configured to measure changes in resistance within the hybrid dual spin valve, complete the sensor. A method for producing a hybrid dual spin valve sensor includes providing such a sensor wherein the magnetization orientations of the two antiferromagnetic layers are disordered, followed by processing at a first temperature and a second temperature. Processing at the first temperature is used to set the magnetization orientation of the antiferromagnetic layer with the higher blocking temperature. Processing at a lower second temperature is used to set the magnetization orientation of the antiferromagnetic layer with the lower blocking temperature such that it is antiparallel to the magnetization orientation of the antiferromagnetic layer with the higher blocking temperature.

Hybrid dual spin valve sensor and method for making same

A system and method for providing a spin valve is disclosed. The spin valve is formed on a substrate. In one aspect, the method and system include providing a seed layer including NiFe above the substrate and providing an antiferromagnetic layer on the seed layer. The seed layer provides the desired texture for the antiferromagnetic layer. The seed layer could include NiFeCr, NiFeNb, NiFeRh, or a NiFe/Cu multilayer. The method and system further include providing a pinned layer above the antiferromagnetic layer, the pinned layer being exchange coupled to the antiferromagnetic layer, providing a spacer layer above the pinned layer and providing a free layer above the spacer layer. In a second aspect, the method and system include providing a seed layer including Cu instead of NiFe. In a third aspect, the method and system include providing a synthetic antiferromagnetic layer in lieu of the antiferromagnetic layer and the pinned layer. In this aspect, the seed layer provides the desired texture for the synthetic antiferromagnetic layer. Note that in any aspect, the spin valve can include a bottom spin valve or a dual spin valve.

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Fremont, CA, United States of America

Ningjia Zhu