Two-Dimensional Imaging of Giant Magnetoresistance with Improved Sensitivity

Two-dimensional images of giant magnetoresistance (GMR) using an infrared (IR) camera in the 8-12 mum wavelength regime are presented. Remote imaging of GMR involves the use of an IR camera to remotely sense changes in the emissivity of a thin film when a magnetic field is applied through a change in effective temperature, which is shown to be approximately linearly related to the GMR. Operating in the longer wavelength regime offers advantages in the theoretical connection between emissivity and GMR and also in the matching of the peak wavelength of the radiated flux with sample temperature. The GMR images obtained at 8-12 mum demonstrate an improvement in the correlation between GMR and emissivity change over previous work performed at 3-5 mum.