Construction of magnetization reversals of ring and square thin films of Ni80Fe20 using magnetic force microscopy

Submicron ring and square thin films of Ni80Fe20 were employed to investigate their magnetization reversals by using magnetic force microscopy (MFM) with a modulus of oscillation amplitude and phase shift. Statistical hysteresis loops of magnetization reversals and magnetic transitions in ring and square thin films of Ni80Fe20 are constructed by averaging the enhanced MFM image contrasts of selected corner areas of the thin films. The hysteresis results demonstrate that the ring thin films of Ni80Fe20 have only two magnetic states, which are fewer than the square thin films of Ni80Fe20.