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Scanning Magnetoresistive Sensors Used in Recording and Bubble Sensing Applications

IP.com Disclosure Number: IPCOM000083632D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Bajorek, CH: AUTHOR [+3]

Abstract

Scanning methods which selectively activate or reactivate one or several magnetoresistive sensors of an array are described, which reduce crosstalk noise in such applications.

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Scanning Magnetoresistive Sensors Used in Recording and Bubble Sensing Applications

Scanning methods which selectively activate or reactivate one or several magnetoresistive sensors of an array are described, which reduce crosstalk noise in such applications.

The physical properties of magnetic materials used in fabricating magnetoresistive sensors and which are useful in controlling their behavior are magnetostriction, anisotropy, Curie temperature, saturation field, conductivity, exchange coupling to adjacent material and coercivity. The methods by which such properties can be affected are electromagnetic fields, magnetostatic fields, heat, stress, and light.

The interaction between the above sources and properties can be direct or indirect. In terms of the relatively high-flow rates of data in current recording and detecting situations (in the Khz to tens of Mhz range), the implementation of these interactions requires the ability to select or activate sensors at very high speeds. This capability can be achieved by several scanning schemes. These are, acoustical scanning, optical scanning, electronic scanning and electromagnetic scanning. The first three scanning methods are relatively slow, while the last is very fast and perhaps beyond the realm of practicality. The significance of these properties, their interaction with the mentioned sources and the merits of scanning can be best understood from the following examples.

1.) For a description of acoustical scanning which utilizes the interaction between stress and magnetostriction of a magnetic sensor, consult articles by D.
A. Thompson and C. H. Bajorek et al, IBM Technical Disclosure Bulletin, Vol. 17, No. 10, pages 3173 and 3174, and Vol. 17, No. 11, pages 3498 to 3500, March and April 1975, respectively.

2.) For a description of electronic scanning of discrete piezoelectric- magnetoresistive film devices (interaction between stress and magnetostriction), consult an article by E. G. Lean et al, IBM Technical Disclosure Bulletin, Vol. 17, No. 12, May, 1975 pages 3751 and 3752.

3.) For a description of electronic scanning resulting in sequential activation of current flow i...