Browse Prior Art Database

Resistive Element for Bias and Noise Cancellation of Magnetoresistive Head

IP.com Disclosure Number: IPCOM000082880D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Nepela, DA: AUTHOR [+2]

Abstract

A batch fabricated shielded magnetoresistive (MR) head with a single MR layer utilizes a nonmagnetoresistive resistive (R) layer, for both MR layer biasing and noise cancellation.

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Resistive Element for Bias and Noise Cancellation of Magnetoresistive Head

A batch fabricated shielded magnetoresistive (MR) head with a single MR layer utilizes a nonmagnetoresistive resistive (R) layer, for both MR layer biasing and noise cancellation.

When sense current I(s) flows through the head to ground, information recorded on the media as magnetic manifestations will be represented as electrical signals at the differential amplifier output. An additional layer R, preferably having an electrical resistance and thermal properties approximately equal to that of the MR layer, is placed parallel to the MR layer. The R and MR layers together with the differential amplifier cancels the thermal noise spikes by common-mode rejection. Suitable electronic amplification can be employed to compensate for unequal properties between the layers, if necessary.

For an R layer which is nonmagnetic and not magnetoresistive, the MR layer can be biased by the portion of the current I(s) through the R layer. The MR layer is centered between the shields. The shields may be made of any high- permeability material. Suitable insulation may be placed among the layers and shields. The R layer can be an electrically conductive permanent magnet to provide additional bias for the MR layer. The conductive permanent magnet R layer is similarly connected to the differential amplifier for common-mode cancellation of thermal noise spikes.

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