Applications of Magnetic Force Microscopy

Abstract

Magnetic force microscopy (MFM) is well suited to be applied to a wide range of topics encountered in a magnetic recording environment. Imaging and characterization of magnetic recording components s~ch as write heads, MR heads and transitions written on various media are reviewed in this article. MFM can also be used to intentionally create (i.e. write) magnetic structures. Contributions of MFM to the understanding of magnetic reversal and switching phenomena of small particles are summarized.

Effect of liquid on the magnetic force microscope imaging

“…The forces detected by MFM are purely magnetic static forces and they depend on the interactions of the magnetic dipole moment of the magnetic tip and the measured sample [17]. For the phase shift △φ MFM imaging method, the phase signal of every point of the scanned area is recorded.…”

“…The magnetic force acting on a volume element dV' in the tip can be given by [19][20][21] dF=μ 0 ▽(M(r')·H(r+r'))dV' (2) where µ 0 is the magnetic permeability of free space, M(r') is the magnetization of the volume element in the tip, and H(r+r') is the stray field from the sample to the tip [17]. The tip can be simple to be a point probe with one magnetic element, then the magnetic force can be rewritten as [22] F m =μ 0 ▽(m·H) (3) where m is the effective dipole moment of the tip.…”