Regensburg 2025 – scientific programme
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MA: Fachverband Magnetismus
MA 37: Magnetic Imaging Techniques
MA 37.10: Talk
Thursday, March 20, 2025, 17:30–17:45, H16
Magnetic Force Microscopy: High Quality-Factor Two-Pass Mode — •Christopher Habenschaden1, Sibylle Sievers1, Alexander Klasen2, Andrea Cerreta2, and Hans Werner Schumacher1 — 1Physikalisch-Technische Bundesanstalt, 38116 Braunschweig — 2Park Systems Europe GmbH, 68199 Mannheim
Magnetic Force Microscopy (MFM) is an effective technique for characterizing magnetic micro- and nanostructures, typically detecting interactions between a magnetically coated tip on an oscillating cantilever and the sample. MFM sensitivity is enhanced under vacuum conditions due to the higher cantilever quality factor (Q-factor), which significantly improves force sensitivity. However, the commonly used two-pass mode in MFM faces challenges under vacuum, as the high Q-factor can lead to tip crashing when surface forces overpower the restoring force during topography imaging.
Here, we present a novel approach for high-sensitivity vacuum MFM measurements while maintaining stable topography detection. Implemented on a Park Systems NX-Hivac AFM, this method modifies the two-pass mode to create a high Q-factor two-pass mode [1]. In the first pass, the cantilever's Q-factor is artificially lowered to ensure stable non-contact topography imaging. In the second pass, a phase-locked loop (PLL) measures the frequency shift, maintaining the maximum Q-factor for optimal sensitivity in magnetic field measurements. This approach prevents tip crashes during the first pass and eliminates non-linear phase response in the second pass, ensuring robust and precise measurements. [1] Rev. Sci. Instrum. 95, 113704 (2024).
Keywords: MFM; Magnetic Force Microscopy; Vacuum; Q-Factor; Two-Pass Mode