Scanning magnetoresistance microscopy (SMRM): Imaging with a MR head

Abstract

We have developed a new scanning magnetic microscopy that uses commercial magnetoresistive (MR) record/playback heads as sense probes. A high-resolution, linearized positioning stage is used to raster scan a magnetic sample with respect to the MR head while the head is in physical contact with the sample. An upper bound on the spatial resolution of the scanning magnetoresistance microscope (SMRM) is 100 nm in the “downtrack” direction and 1–2 μm in the “crosstrack” direction of the head. Magnetic force microscopy has better spatial resolution than SMRM, but SMRM gives a more quantifiable signal since the MR head response can be calibrated in a uniform external field. Furthermore, SMRM has the unique ability to apply localized fields to the sample via the inductive write element.