Magnetic force microscope
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A atomic force microscopy (NC-AFM). Unlike NC-AFM, magnetic materials are used for the sample and tip, so that not only the atomic force but also the magnetic interaction are detected. Many kinds of magnetic interactions are measured by MFM, including magnetic dipolar interaction.
In MFM measurements, the magnetic force between the sample and tip is given by:
- F = (m .∇)H
- m: magnetic moment of the tip
- H: magnetic stray field from the sample
Because the magnetic stray field from the sample will affect the magnetized state and vice versa, in most cases it is difficult to obtain quantitative information from the MFM measurement. To interpret the information quantitatively, the configuration of the tip must be known. With this measurement, a typical resolution of 30 nm can be achieved (Abelmann, 1998). Although resolutions as high as 10 nm are attainable (SwissProbe, February 2008).
A potential method of increasing the resolution would involve using an electromagnet on the tip instead of a permanent magnet. Enabling the magnetic tip only when placed over the pixel being sampled could increase the resolution.
[edit] References
- L. Abelmann, S. Porthun, M. A. M. Haast, J. C. Lodder, A. Moser, M. E. Best, P. J. A. Schendel, B. Stiefel, H. J. Hug, G. P. Heydon, A. Farley, S. R. Hoon, T. Pfaffelhuber, R. Proksch, K. Babcock (1998). "Comparing the resolution ofƏÊ magnetic force microscopes using the CAMST reference samples". J Magn Magn Mater 190: 135–147. doi:.
- SwissProbe. Quantum leap in hard disk technology. Retrieved on February 27, 2008.
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