Browse Prior Art Database

A Magnetoresistive Center Tap with Minimum Loss of Active Sensor Width

IP.com Disclosure Number: IPCOM000109459D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 49K

Publishing Venue

IBM

Related People

Aboaf, JA: AUTHOR [+3]

Abstract

The following relates to a method for reducing distortion in magnetic recording applications of center tapped magnetoresistive (MR) designs. In a center tapped sensor, the center tap is made by shaping the physical center of the MR sensor. This is usually a wide area, about 20 to 30 microns, and the current flow lines adjacent to the bend of the center tap destroys the bias magnetization on each side. A very small center tap at the physical center of the sensor cannot be made easily because of photolithographic constraints.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

A Magnetoresistive Center Tap with Minimum Loss of Active Sensor Width

      The following relates to a method for reducing distortion in
magnetic recording applications of center tapped magnetoresistive
(MR) designs.  In a center tapped sensor, the center tap is made by
shaping the physical center of the MR sensor.  This is usually a wide
area, about 20 to 30 microns, and the current flow lines adjacent to
the bend of the center tap destroys the bias magnetization on each
side.  A very small center tap at the physical center of the sensor
cannot be made easily because of photolithographic constraints.

      This can be done using a very small center tap, about 3
microns, as follows:  A liftoff of 3000 A of an alumina film on the
MR element with a 3 micron window in the center.  A shield, a
magnetic film of high permeability such as permalloy is subsequently
deposited on the alumina and makes ohmic contact with the MR element
forming the electrical center tap.  For multi-track heads, the
shields are electrically common and connected to a ground lead by
methods well known in the art.  The shield shape also contains a
cutout region which forces the center tap current to follow closely
parallel to the MR sensor after the current leaves the MR center tap.
This center tapped MR sensor provides for optimized current flow at
the center contact eliminating center tap spreading effects and
consequently Barkhausen noise.

      Disclosed anonymously.