Energy dissipation measurements in frequency-modulated scanning probe microscopy

Abstract

Local dissipation measurements by scanning probe microscopy have attracted increasinginterest as a method for probing energy losses and hysteretic phenomena due to magnetic,electrical, and structural transformations at the tip–surface junction. One challenge of thistechnique is the lack of a standard for ensuring quantification of the dissipation signal. Inthe following, we explored magnetic dissipation imaging of an yttrium–iron garnet (YIG)sample, using a number of similar but not identical cantilever probes. Typicalfrequency-dependent dispersion of the actuator–probe assembly commonly approached ± 1 partin 103 Hz − 1, much larger than the minimum detectable level of ± 1 partin 105 Hz − 1. This cantilever-dependent behavior results in a strong crosstalk between the conservative(frequency) and dissipative channels. This crosstalk was very apparent in the YIGdissipation images and in fact should be an inherent feature of single-frequency heterodynedetection schemes. It may also be a common effect in other dissipation imaging, even downto the atomic level, and in particular may be a significant issue when there are correlationsbetween the conservative and dissipative components. On the other hand, we present asimple method for correcting for this effect. This correction technique resulted inself-consistent results for the YIG dissipation measurements and would presumably beeffective for other systems as well.