Western Digital (fremont), Inc.

Read Rite Corporation

Geoff Anderson

Yiming Huai

Mahendra Pakala

Wenjie Chen

Ningjia Zhu

A spin valve device includes a non-magnetic enhancement layer adjacent an ultra thin free layer. The thickness of the free layer may be less than the mean free path of a conduction electron through the free layer. The GMR ratio is significantly improved for free layer thicknesses below 50 &#x212b;. The enhancement layer allows electrons to travel longer in their spin state before encountering scattering sites. The electronic properties of the enhancement layer material can be matched with the adjacent free layer without creating a low resistance shunt path. Because the free layer may be made ultra thin and the enhancement layer is formed of a nonmagnetic material, less magnetic field is required to align the free layer, allowing for improved data density. Also, the enhancement layer allows for effective bias point control by shifting sensor current density distribution.

Spin valve sensor having a nonmagnetic enhancement layer adjacent an ultra thin free 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.

Growing community of inventors

Pleasanton, CA, United States of America

Geoff Anderson