High-Frequency Magnetic Field Energy Imaging of Magnetic Recording Head by Alternating Magnetic Force Microscopy (A-MFM) with Superparamagnetic Tip

Recent progress in the development of high-frequency (HF) magnetic materials and devices requires the HF imaging of magnetic field and magnetic field response with high spatial resolution. In this work, we proposed HF Alternating Magnetic Force Microscopy (A-MFM) with a superparamagnetic tip to image magnetic field energy near the sample surface. Magnetic field with a frequency from 100 kHz to 1 GHz was emanated by a writing head used for perpendicular magnetic recording. Applied HF magnetic field is amplitude modulated, and magnetic energy determines the frequency modulation of cantilever oscillation in the framework of A-MFM. The frequency modulated oscillation was caused by low frequency alternating magnetic force, which was generated by the interaction between the amplitude modulated AC magnetic field and superparamagnetic tip.