Spin-contrast in non-contact SFM on oxide surfaces: theoretical modelling of NiO(001) surface

Searching atomic spin contrast on nickel oxide (001) by force microscopy

“…Calculations have shown that very small tip-sample distances are necessary to observe spin contrast even though tip ion instabilities may result at very small distance. 31 Here, we have been able to image in the repulsive regime with positive frequency shifts and generally at distances close to the bulk neighbor distance, where optimal spin contrast is expected. 26 While tips remained stable, we did not observe spin contrast.…”

“…19 A modeling of the NiO͑001͒ surface interacting with a spinpolarized H atom ͑weakly reactive͒ and a spin-polarized Fe atom ͑strongly reactive͒ finds that the difference in force over opposite spin atoms should be detectable with the AFM for a tip-sample distance smaller than 4 Å or for imaging close to the repulsive regime. 20 However, at such short distances, the chemical bonding forces can become strong and it was speculated that ion instabilities may become apparent. Elongations of the tip and the sample atomic bonds are no longer negligible and atoms may even become displaced.…”

Imaging and Characterization of Magnetic Micro- and Nanostructures Using Force Microscopy

“…This is, for example, reflected in the typical probe-sample distance, which is below 1 nm in MExFM and ranges between few 10 nm and some 100 nm in MFM or MRFM. Although calculations in the 1990s suggested the possibility of MExFM [239][240][241], the first trails were not successful [242][243][244], and it took several years to find a suitable setup and system to experimentally demonstrate the concept of MExFM [84]. These measurements already showed the impressive capability of MExFM to create spin maps with true atomic resolution.…”

Surface Science Tools for Nanomaterials Characterization

“…An important area of scientific inquiry with great technological implications is friction [241]. Despite the fact that friction is ubiquitous in our daily lives and a major source of energy dissipation in industrial processes, the basic physical laws that govern this particular phenomenon at the nanometer scale are still not well known [242].…”