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Magnetic Performance and Stability Test for Magnetoresistive Sensors

IP.com Disclosure Number: IPCOM000115830D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Abboud, SE: AUTHOR [+4]

Abstract

A Magnetic performance test for a Magnetoresistive (MR) recording head sensor is disclosed. Advances over prior art include "stressing" to determine the magnetic stability of the device.

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Magnetic Performance and Stability Test for Magnetoresistive Sensors

      A Magnetic performance test for a Magnetoresistive (MR)
recording head sensor is disclosed.  Advances over prior art include
"stressing" to determine the magnetic stability of the device.

      This method is useful for testing MR heads early in the
manufacturing process in order to determine if they are within
performance specifications in terms of output and stability.

      The MR head in the form of a row, slider or suspended slider is
placed in the magnetic field of an electromagnet.  The magnet
supplies a sinusoidal magnetic field with a frequency of 1000 Hertz
and a peak amplitude of at least 100 Oersted.  The MR sensor is
connected to suitable electronics to measure the transducer output.

      Test data includes the mean and sigma for the peak-to-peak
amplitude, nonlinearity of the response, nonrepeatable and repeatable
irregularities in the response and the sensor electrical resistance.

      A novel feature that gives a better measurement of the head
stability is to "stress" the MR sensor in between cycles.  The
stresses used involve a combination of magnetic field pulses, write
head excitation and toggling the MR bias current in both directions.
These stresses can be done with the MR bias current either on or off.

      The circuitry corrects for undesirable head pickup of the high
frequency magnetic field by measuring the response of the head with
the bia...