Pressure-enhanced giant magnetoresistance in Fe/Cr magnetic multilayers

The magnetoresistance of Fe/Cr magnetic multilayers (MMLs) on the 1 st and the 2 nd peaks has been measured at high pressure up to 3 GPa at low temperature in order to make clear the characteristics of the giant magnetoresistance (GMR) under high pressure. The GMRs of the MMLs on the 2 nd peak are found to be enhanced strongly by applying pressure whereas those of 1 st peak MMLs decrease with increasing pressure. The magnitude of GMR of the 2 nd peak MMLs becomes about twice or more at 2 GPa compared with the value at ambient pressure. The large difference in the pressure dependences is explained by assuming a pressure-induced crossover in the interlayer exchange coupling from the biquadratic to the bilinear spin arrangements.