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MR TRANSDUCER (AMR) WITH COMMON MODE AND THERMAL ASPERITY NOISE REJECTION

IP.com Disclosure Number: IPCOM000013989D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue

IBM

Abstract

A magnetic recording sensor for use in close proximity with recording medium having thermal noise canceling structure. As recording sensors are used in closer proximity to the recording media the sensor is more susceptible to thermally induced noise such as baseline wander or thermal asperities. If a conductor is placed in the same gap region as the sensor but is electrically insulated from the sensor then a non-magnetic thermally induced signal from this conductor can be electronically subtracted from the total sensor signal. The resulting signal will contain the magnetic readback signal without the thermally induced noise. The conductor can be made of any conducting material including, conveniently, the same material as the sensor (but without magnetic biasing). The insulating layer can be made of any insulating material such as alumina. For best noise cancellation the thermal properties and physical volume of the conductor should be similar to that of the sensor. The electronic cancellation can be conveniently accomplished with a differential amplifier with either current bias or voltage bias applied to both the sensor and conductor. 1