Browse Prior Art Database

Magnetoresistive Read Heads

IP.com Disclosure Number: IPCOM000081927D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Bate, G: AUTHOR [+3]

Abstract

Magnetoresistive (MR) heads for reading magnetic recording media have been described in the literature. Generally, they have consisted of a magnetoresistive element through which a sense current flows. When acted upon by varying magnetic fields, such as those from data recorded on a magnetic recording media, the resistance of the magnetoresistive element varies. These changes in resistance are then detected as a change in current through the element and interpreted as data by associated circuitry.

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Magnetoresistive Read Heads

Magnetoresistive (MR) heads for reading magnetic recording media have been described in the literature. Generally, they have consisted of a magnetoresistive element through which a sense current flows. When acted upon by varying magnetic fields, such as those from data recorded on a magnetic recording media, the resistance of the magnetoresistive element varies. These changes in resistance are then detected as a change in current through the element and interpreted as data by associated circuitry.

In order to distinguish between magnetic fields of opposite polarities, it has been the practice to bias the magnetoresistive element with a strong magnetic field. See: R. P. Hunt, "A Magnetoresistive Readout Transducer," IEEE Mag. Trans. Mag-7, 150 (1971). More recently, French Patent 2.165.206 has taught that a magnetoresistive read head need not be magnetically biased, if the easy axis of the MR film is at an angle to the direction of the sense current flow.

The diagrammatically shown heads are useful for magnetoresistive reading of magnetic media over a broad range of fields emanating from the media. Referring to Fig. 1, an MR head is shown in which the MR element is perpendicular to the media to be read and situated between two magnetic shields, for example of ferrite or high-permeability metal. The shields serve to block all magnetic fields from the MR element, except for those fields emanating from magnetic dipoles in the media in the immediate vicinity of the gap between the shields.

As illustrated, the easy axis <EA> of the MR element is inclined at an angle to the direction of the sense current (j), much as in the French patent. Also shown, diagrammatically, is the ve...