Giant magnetoresistive spin valve bridge sensor

Author

Spong, Jaquelin K. ; Speriosu ; Fontana, Robert E., Jr. ; Dovek, Moris M. ; Hylton, Todd L.

Author_Institution

IBM Almaden Res. Center, San Jose, CA, USA

Volume

32

Issue

2

fYear

1996

fDate

3/1/1996 12:00:00 AM

Firstpage

366

Lastpage

371

Abstract

We describe the design, fabrication, and performance of a “spin valve” magnetic field sensor based on the giant magnetoresistive effect. The sensor is a balanced, four resistor, fully biased, Wheatstone bridge network with bipolar output. The devices described here show magnetoresistance ratios ΔV/V=ΔR/R=6%, saturation fields of 25 Oe, and a Johnson limited noise floor of 2.6 μOe/(Hz)^1/2. The linearity of the device is +/-2% of the full scale amplitude, with a hysteresis of 1% over the linear range. Fabrication of this device requires a novel approach to setting the directions of the antiferromagnetic exchange layers that bias the sensor. As compared to bridges based on the anisotropic magnetoresistance effect, these devices offer superior signal amplitude and linearity. To our knowledge this is the first report of such a device

Keywords

Permalloy; bridge circuits; bridge instruments; giant magnetoresistance; magnetic multilayers; magnetic noise; magnetic sensors; magnetoresistive devices; Johnson limited noise floor; NiFe-Co-Cu-Co-NiFe-FeMn; Wheatstone bridge network; antiferromagnetic exchange layers; bipolar output; giant magnetoresistive spin valve bridge sensor; magnetoresistance ratios; permalloy spin valve multilayer; saturation fields; signal amplitude; signal linearity; spin valve magnetic field sensor; Anisotropic magnetoresistance; Bridge circuits; Fabrication; Giant magnetoresistance; Linearity; Magnetic noise; Magnetic sensors; Resistors; Sensor phenomena and characterization; Spin valves;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.486520

Filename

486520