Authors: Y.H. Wu, G. Han and Y.K. Zheng
Affilation: National University of Singapore, Singapore
Pages: 715 - 718
Keywords: MFM tips, synthetic structure, point-dipole response
Recently, we have developed a synthetic MFM tip consisting of two ferromagnetic layers and a non-magnetic spacer . The two ferromagnetic layers are coupled antiferromagnetically so that the MFM works in a differential detection mode. This has led to the enhancement of high-frequency component against the lower frequency counterpart. Experimentally we have also found that the synthetic tip functions as a point-dipole tip. In this paper, we will present a detailed theoretical analysis of the tip and compare the results with experimental data. The effect of spacer thickness on the imaging characteristics of the MFM tip will also be discussed.  Y. H. Wu et al, Appl. Phys. Lett. 82, 1748-1750 (2003).