Browse Prior Art Database

Corrosion Free Magnetoresistive Read Head

IP.com Disclosure Number: IPCOM000081577D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 50K

Publishing Venue

IBM

Related People

Bajorek, CH: AUTHOR [+2]

Abstract

A method for making a magnetoresistive head has been devised, wherein the final magnetoresistive read head has been encapsulated and hermetically sealed from the atmosphere prior to a grinding operation, used to accurately position such sealed head from a magnetic storage medium.

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Corrosion Free Magnetoresistive Read Head

A method for making a magnetoresistive head has been devised, wherein the final magnetoresistive read head has been encapsulated and hermetically sealed from the atmosphere prior to a grinding operation, used to accurately position such sealed head from a magnetic storage medium.

The performance of any recording device critically depends on the separation between the transducer and the medium. This separation usually consists of two parts: 1) the distance between the transducer surface exposed to the medium and a specific detail of the sensing portion of the transducer, and 2) the distance between that surface and the medium. This surface is typically defined by mechanical grinding and lapping techniques.

The ease and accuracy with which this surface can be established relative to the sensing portion of the transducer can be greatly improved, by using a thin film lapping resistor in close proximity to the sensing portion of the transducer. The grinding and lapping operation removes parts or all of this resistor and the change of resistance will signal the location of the surface. This concept as it applies to an inductive head is exemplified in the prior art, as shown in Figs. 1 and 1a.

Recording head R will comprise a magnetoresistive (MR) sensing element 2, of the order of 200 Angstroms thick and made of permalloy or the like, deposited on a suitable insulated substrate, not shown. Leads 4 and 6 are connected to such MR element 2 and gold 8, or other noble metal, is deposited over such leads. A conducting element 10 is located at a distance d away from MR element 2. The head is covered with a suitable passivating overcoat 25 i.e., Al(2)O(3). During the lapping process along path A-A, the resistance of conductor 10 is monitored continuously by meter 12. When conductor 10 is sufficiently abraded so that either electrical conduction is interrupted or changed discontinuously in its value, a signal is generated to stop the lapping process.

However, it has been found that in devices of the type described in Fig. 1, the exposure of either or both the residual metallic conductor 8 and leads 4 and 6 to the surface exposed to the storage medium, equivalently to the ambient atmosphere, combined with their intrinsic connection to the sensing portion 2 of the transducer, can lead to fail...