Near field and magnetic field generator for thermal assisted magnetic recording

We fabricated a generator that produces optical near field and magnetic filed in a nanometer area for achievement of thermally assisted magnetic recording. The generator consists of an embedded wire with a bottleneck structure on a SiO₂ substrate. The magnetic field is mainly generated around the bottleneck structure by feeding current through the wire. The near field is produced on an edge of the narrow wire by focusing a laser beam on the bottleneck structure through the backside of the substrate. The generator is anticipated as application to control ordering, chirality, and phase transition of diamagnetic materials in a nano-area. We confirmed the three-dimentional localization of near field in the nanometer size around the bottleneck structure by means of a near field scanning optical microscope.