# Unraveling Dissipation-Related Features in Magnetic Imaging by Bimodal Magnetic Force Microscopy
## 3 Results and Discussion
(**f**) is a zoom of the MFM image (**b,g**) is a zoom of the dissipation map corresponding to the 1 st mode (**c**) where rings and stronger bright contrast that correspond to dissipation-related features can be easily distinguished superposed to the magnetic domain configuration (marked with green arrows). (**h,i**) are the equivalent zooms of the images corresponding to the second mode (**d,e**) where it is not clear the presence of the dissipation related features at the same positions (green arrows). canting of the spins into the magnetic domains and to the sudden changes in the domain structure, the 2 nd mode image (Figure 2e) has no significant contrast. The Figure 2f-j summarize the results obtained with a low-moment-low-coercive probe. In this case, the stray field of the sample could induce spin canting at the tip apex while the magnetic moment of the tip is not sufficient to modify the configuration of the sample. For that reason, instead of the typical jumps in the MFM images some rings and bubbles are observed (Figure 2g,i). Those features correspond to the spin switching or canting processes at the tip apex due to the influence of the sample stray field. They are visible only in the 1 st mode MFM map (Figure 2g), however, the 2 nd mode MFM image is free of this undesirable effects. To understand the differences between the two flexural modes we must focus on the amplitudes of both modes. In the bimodal MDFM experiment shown above A\({}_{2}\) is much smaller than A\({}_{1}\). [PERSON] et al. [13] already predicted the relationship between the shape of the dissipation features and the tip-sample distance and the free oscillation amplitude. When the tip is oscillating in front of the sample, it is visiting regions with different stray field. Larger amplitudes lead to higher variation of the stray field and thus to the increase of the dissipation. However, the influence of the tip stray field onto the domain walls depends only on the tip stray field and on tip-sample distance. To explore the origin of the different features observed in the bimodal MFM images, experiments with different A\({}_{1}\)/A\({}_{2}\) values have been carried out. Figure 2: Different tip-sample interactions. Left panel corresponds to a Bimodal MDFM experiment with a high moment magnetic tip and right panel corresponds to a similar experiment with a low moment MFM tip: (**a–f**) topography of the sample (CoCr film), (**b,g**) frequency shift of the first mode during the second scan where the magnetic signal is detected. (**d,i**) phase of the second mode during the retrace scan. (**c,h**) are the dissipation maps calculated with Equation (1) and the parameters corresponding to the 1 st mode (**e,j**) are the dissipation maps of the 2 nd mode. All the dissipation maps are calculated during the retrace scan. The black arrows indicate tip induced magnetic reversal whereas blue arrows indicate dissipation-related features due to spin canting at the tip apex. Images size: 0.7 \(\upmu\)\(\times\) 0.7 \(\upmu\)m. A\({}_{1}\) = 20 nm. A\({}_{2}\) = 0.75 nm. Z lift distance = 30 nm. As reported in reference [35], on some occasions the conditions and parameters that give us the maximum dissipation contrast are not the same as those that lead to maximum phase or frequency shift contrast. In fact, [PERSON] and coworkers recommend a choice of the parameters as a function of the quantity that is most relevant to the study. In Figure 3 we demonstrate that increasing the value of the amplitude of the 2 nd mode (keeping fixed A1) could drastically change the information that we can achieved in the magnetic images. In Figure 3d the yellow arrows indicate the bright features corresponding to changes of the spins of the tip apex as previously reported. Now this effect is present in both modes (yellow arrows) whereas with the typical ratio between amplitudes (A1/A2 >> 1) it only appears in the magnetic image obtained with the first mode (green arrows).