Local probing of the giant magnetoresistance

We have contacted the tip of a scanning tunneling microscope (STM) to a Co/ Cu magnetic multilayer to locally measure the giant magnetoresistance (GMR) of the multilayer. Apart from a point-contact GMR, the measured MR also re flects a magnetostriction effect in the STM. The resulting GMR ratios are t ypically 10%, with occasional ratios up to 60%. We attribute spot-to-spot v ariations of the ratio to differences in the local structure of the magneti c multilayer. (C) 2000 American Institute of Physics. [S0003-6951(00)00641- 0].