Magnetoresistive head with integrated bias and magnetic shield layer
AssigneeMinnesota Mining and Manufacturing Company
InventorsTheodore A. Schwarz, Peter G. Bischoff, Chak M. Leung, Johnny C. Chen, Pradeep Thayamballi
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Abstract
A thin-film magnetoresistive playback head having films providing magnetic shielding and magnetic bias. At least one of the magnetic shield layers is also conductive so that the functions of shielding and biasing are combined. Preferably, both shield layers are conductive. A multiple element channel head is disclosed in which the magnetic/conductive layers extend in series from one transducer section to the next, allowing a single bias current to bias all of the sections.
Claims13
A thin film magnetic head for interacting with information recorded at magnetized areas spaced along a recording medium, comprising
- a substrate having a non-conductive, non-magnetic surface, an edge defining a first plane adapted to be positioned adjacent to a said recording medium, and having deposited thereon;
- a magnetoresistive transducing element including at least a single layer of material exhibiting the magnetoresistive effects and having an edge lying in said first plane,
- a pair of magnetically permeable shield layers each of which is disposed adjacent to an opposite side of said magnetoresistive element and having opposing faces spaced apart a fixed distance on the order of and less than the shortest wavelength of said recorded information, an edge of each of the two permeable layers also lying in said first plane, at least one of said magnetically permeable layers being formed of an electrically conductive material,
- an insulating layer interposed between the at least one magnetoresistive element and the electrically conductive, magnetically permeable layer, thereby allowing current passing through said conductive material to create an associated magnetic bias field for the magnetoresistive element, while also magnetically shielding said magnetoresistive element to enable reproduction of short wavelength recordings, the thickness of said magnetically permeable layers being not less than three times said fixed distance between the permeable members, and
- means contacting said electrically conductive, magnetically permeable layer for enabling current flow therethrough, the resulting magnetic field biasing said magnetoresistive element.
Dependencies are inferred from the claim text.