Nano-resolution reconstruction of magnetic fields near a magnetic probe using a thin-film magnetic sensor

Abstract

This paper presents the nano-resolution measurement of magnetic fields near a magnetic probe using a thin-film magnetic sensor. The measurement method consists of a process, where the thin-film magnetic sensor is scanned over the sample, followed by a deconvolution scheme. In the scanning process, the thin-film magnetic sensor is scanned over the sample perpendicularly to the sensor. The sample is rotated horizontally under the sensor so that data measurements are obtained at different angles and positions. The deconvolution can be performed using existing methods, which are common in the field of computed tomography. An experiment was performed to verify the technique's capability of measuring a magnetic field using a thin-film magnetic sensor. Currently, thin-film magnetic sensors are used as reading heads in hard drive disks (HDD). At present, the film thickness of the heads is less than 10nm. Previously, the resolution of the measurement was limited by the width of the sensor (ie. 100nm) which is always greater than the thickness. However, the new technique has the same resolution as the film thickness (ie. 10nm).