Relationship between Magnetization State of Ferromagnetic Tip and Observed Results in a Magnetic Force Microscope

摘要

This paper investigates the relationship between image obtained by Magnetic Force Microscope (MFM) and the Magnetization distribution in a ferromagnetic tip. Stray field of a ferrite recording head is measured by an MFM using Co coated ferromagnetic tip. Asymmetrical images are obtained with respect to the current flow. To understand the images obtained by MFM, finite element calculations are carried out and derivatives of force acting on the tip are obtained, where both tip-head magnetic interaction and nonlinearity of Co tip and head material are taken into account. By comparing the MFM image and calculated derivative of force, close agreement is found. The relationship between calculated magnetization states of Co tip and the MFM images is also discussed. We found that it is indispensable to understand the magnetization state of a ferromagnetic tip in order to understand the MFM images．