HP Labs Technical Reports

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Magnetoresistance Overview

Nickel, Janice



Abstract: Magnetoresistance, the change of a material's resistivity with the application of a magnetic field, is a well known phenomenon. The magnitude of the effect in materials used in the recording industry has historically been very small, only about 2% at room temperature for "anisotropic" magnetoresistant materials. In 1988, Baibich et al reported magnetoresistance effects of up to 50% at low temperature in "giant" magnetoresistive multilayer structures. More recently, effects of 99.9% change in resistivity have been discovered in the perovskite system La (sub1 - subx) Ca (subx) MnO (sub3) termed "colossal" magnetoresistance. Magnetic read heads utilizing "anisotropic" magnetoresistance have been successfully fabricated and marketed. Prototypes of read heads utilizing "giant" magnetoresistance have also been made. The distincly different materials and mechanisms responsible for the varied magnetoresistance effects - ordinary, anisotropic, giant and colossal - will be discussed. Also various designs of magnetic read heads utilizing the "anisotropic" and "giant" magnetoresistive materials are presented.

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