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J. Hafner, C. Berger, D. Platz, U. Schmid:
"Plates as Probes for Atomic Force Microscopy in Liquid Environments";
Talk: XXI. Linz Winter Workshop 2019, Linz; 02-01-2019 - 02-03-2019; in: "XXI. Linz Winter Workshop 2019", (2019), 1.

Conventionally used atomic force microscopy (AFM) probes are micromachined rectangular beams which are much longer than they are wide. In operation, the beams usually vibrate in one of the one-dimensional modes of the Euler-Bernoulli beam theory. However, for the investigation of biological samples in liquid environments, these modes get extremely damped. In particular, their resonance frequency decreases tremendously, which is very undesirable for High-Speed AFM applications. The state of the art is to reduce the length of the beams to increase their resonance frequency.1 However, these ultra-short beams provide only a very low signal-to-noise ratio. Here, we present a novel concept for AFM probes, which overcome these problems. Instead of a beam, we use a plate that has approximately equal dimensions in length and width. These plates have new modes of vibrations, which are at high frequencies and are only slightly damped in liquids. In Figure 1, we show a micromachined plate and compare its one-dimensional mode with its two-dimensional (roof tile-shape) mode. The impact of various media on the different modes are shown in Figure 2.