Visualization of magnetic domains by near-field scanning microwave microscope

A near-field scanning microwave microscope (NSMM) system was used for the investigation of magnetic properties of a hard disk (HD) under an external magnetic field. To demonstrate local microwave characterization of magnetic domains by NSMM, we scanned the HD surface by measuring the microwave reflection coefficient S11 of the NSMM at an operating frequency near 4.4 GHz. The NSMM offers a reliable means for quantitative measurement of magnetic domains with high spatial resolution and sensitivity.