Browse Prior Art Database

Internally Biased Magnetoresistive Transducer

IP.com Disclosure Number: IPCOM000086824D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Burkhart, RW: AUTHOR [+3]

Abstract

U. S. Patent 3,967,368 discloses a magnetic transducer exhibiting the magnetoresistive (MR) effect made by depositing at least two thin-film layers. In this structure an MR film replaced in an electrical contact with a higher resistivity layer is magnetically biased by a portion of the MR sense current shunted through the nonmagnetic layer. Where the magnetic layer is permalloy, for example, the following process serves to increase both the anisotropy and magnetoresistance of the deposited permalloy. A method of making such a transducer follows:

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Internally Biased Magnetoresistive Transducer

U. S. Patent 3,967,368 discloses a magnetic transducer exhibiting the magnetoresistive (MR) effect made by depositing at least two thin-film layers. In this structure an MR film replaced in an electrical contact with a higher resistivity layer is magnetically biased by a portion of the MR sense current shunted through the nonmagnetic layer. Where the magnetic layer is permalloy, for example, the following process serves to increase both the anisotropy and magnetoresistance of the deposited permalloy. A method of making such a transducer follows:

Step 1: A ferrite substrate is provided.

Step 2: Al(2)O(3) is sputtered over the entire surface of the ferrite substrate.

Step 3: The substrate and Al(2)O(3) are heated to about 150 degrees C and then titanium is vacuum-deposited on the heated substrate at a pressure not to exceed 5x10/-6/ torr.

Step 4: The deposition chamber is allowed to cool and then vented to atmosphere.

Step 5: A vacuum not to exceed 5x10/-6/ torr is reestablished, the substrate and coatings are heated to about 250 degrees C and then permalloy is vacuum- deposited on the titanium at a rate of about 6 to 10 Angstroms per second. After deposition is completed, but before venting, the chamber is allowed to cool.

By utilizing these steps, the resulting permalloy film exhibits both increased anisotropy and magnetoresistance.

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