Robust giant magnetoresistance material system for magnetic sensors

A new, robust giant magnetoresistance (GMR) material system is described that comprises an exchange-biased artificial antiferromagnet. For the exchange biasing Ir18Mn82 is used because of its high blocking temperature. Experiments have demonstrated that this material can withstand magnetic fields larger than 150 kA/m and annealing at temperatures above 275 degrees C without irreversible damage. At higher temperatures the GMR effect starts to decrease due to atomic diffusion; the exchange-biasing effect, however, does not disappear, which means that this is no longer the limiting factor. The excellent magnetic and thermal robustness, combined with the unambiguous asymmetric magnetoresistance curve, makes this GMR material system very suitable for application in (e. g., automotive) sensors. (C) 1999 American Institute of Physics. [S0021-8979(99)38308-0].