A new experimental design for noncontact giant magnetoresistance measurements using the magnetorefractive effect

Electrical magnetoresistance measurements of spin dependent materials or devices are very difficult without surface damaging or sample contamination, especially for thin-film giant magnetoresistance (GMR) multilayers. Moreover, the in situ determination of the GMR profile is almost impossible using electrical measurements. We propose a novel experimental design that allows the convenient measurement of magnetoresistance profiles using a noncontact method based on the magnetorefractive effect. This technique is applicable to metallic samples or devices showing magnetotransport properties and is also suitable for in situ measurements. The experiment involves infrared (IR) reflectivity measurements as a function of the applied magnetic field. By introducing IR optical fibers, the experimental setup has been substantially simplified while the need for costly optical components and time consuming alignments has been eliminated. Theoretical simulations of this experiment are also presented prior to the introduction of the proposed design.