298
D. Passeri et al.
of 10–200 nm [93]. The releasing and precise positioning of the grabbed nanoparticles has not been shown, yet. Nevertheless, the in situ demagnetization of the probe
could allow the release of the NP in a determined position on the surface. CM-MFM
[15] technique, thanks to its capability of in situ magnetizing and demagnetizing the
probe could be applied to vary the magnetization state of the probe and allow the
entrapment, the positioning and the release of the single nanoparticles and, in line of
principle, used for magnetic nanopatterns fabrication.
12.4 Conclusions, Perspectives and Challenges
Due to its lateral resolution, sensitivity, imaging capability, the need for a relatively
simple and widespread experimental setup, minimal/no specific requirements about
sample preparations, capability to operate in air at room conditions as well as in
vacuum or liquid environment, MFM can be considered one of the most effective
and versatile techniques for the characterization of magnetic NPs. In particular, the
potential of MFM for the quantitative characterization of magnetic properties of
single magnetic NPs and, more in general, of nanomaterials, at the nanometer scale
has been widely demonstrated. Also, being sensitive to long-range magnetic forces,
MFM can be used to detect single magnetic NPs in nonmagnetic (e.g., biological)
matrices allowing the characterization of magnetic nanocomposites. Also, MFM can
be used as a tool to assess the presence of ferritin in biological tissues and to analyze
cells labeled with functionalized magnetic NPs. Finally, not only can MFM be used
as an imaging tool, but it can be used to modify the morphology and the magnetic
state of magnetic NPs via mechanical or magnetic nanomanipulation. Despite its
promising performances and encouraging results, however, several issues must be
addressed such as: the enhancement of the sensitivity by developing improved MFM
probes; the removal of nonmagnetic artifacts in MFM signal; the definition and
improvement of lateral and vertical resolution; the comprehensive modeling of tipsample interaction. Addressing these metrological aspects would result in a great
improvement significance of MFM in the study of magnetic NPs, paving the way
to the validation of truly accurate, sensitive and reliable MFM-based nanomagnetic
characterization tools of magnetic NPs and, possibly, towards the development of
MFM-based tomographic methods for the analysis of magnetic NPs in magnetic
nanocomposites.
References
1. G. Binnig, C.F. Quate, C. Gerber, Phys. Rev. Lett. 56, 930 (1986)
2. J. Zhong, J. Yan, RSC Adv. 6, 1103 (2016)
3. Y. Martin, H.K. Wickramasinghe, Appl. Phys. Lett. 50, 1455 (1987)
4. Y. Martin, C.C. Williams, H.K. Wickramasinghe, J. Appl. Phys. 61, 4723 (1987)
5. J.J. Sáenz et al., J. Appl. Phys. 62, 4293 (1987)
D. Passeri et al.
of 10–200 nm [93]. The releasing and precise positioning of the grabbed nanoparticles has not been shown, yet. Nevertheless, the in situ demagnetization of the probe
could allow the release of the NP in a determined position on the surface. CM-MFM
[15] technique, thanks to its capability of in situ magnetizing and demagnetizing the
probe could be applied to vary the magnetization state of the probe and allow the
entrapment, the positioning and the release of the single nanoparticles and, in line of
principle, used for magnetic nanopatterns fabrication.
12.4 Conclusions, Perspectives and Challenges
Due to its lateral resolution, sensitivity, imaging capability, the need for a relatively
simple and widespread experimental setup, minimal/no specific requirements about
sample preparations, capability to operate in air at room conditions as well as in
vacuum or liquid environment, MFM can be considered one of the most effective
and versatile techniques for the characterization of magnetic NPs. In particular, the
potential of MFM for the quantitative characterization of magnetic properties of
single magnetic NPs and, more in general, of nanomaterials, at the nanometer scale
has been widely demonstrated. Also, being sensitive to long-range magnetic forces,
MFM can be used to detect single magnetic NPs in nonmagnetic (e.g., biological)
matrices allowing the characterization of magnetic nanocomposites. Also, MFM can
be used as a tool to assess the presence of ferritin in biological tissues and to analyze
cells labeled with functionalized magnetic NPs. Finally, not only can MFM be used
as an imaging tool, but it can be used to modify the morphology and the magnetic
state of magnetic NPs via mechanical or magnetic nanomanipulation. Despite its
promising performances and encouraging results, however, several issues must be
addressed such as: the enhancement of the sensitivity by developing improved MFM
probes; the removal of nonmagnetic artifacts in MFM signal; the definition and
improvement of lateral and vertical resolution; the comprehensive modeling of tipsample interaction. Addressing these metrological aspects would result in a great
improvement significance of MFM in the study of magnetic NPs, paving the way
to the validation of truly accurate, sensitive and reliable MFM-based nanomagnetic
characterization tools of magnetic NPs and, possibly, towards the development of
MFM-based tomographic methods for the analysis of magnetic NPs in magnetic
nanocomposites.
References
1. G. Binnig, C.F. Quate, C. Gerber, Phys. Rev. Lett. 56, 930 (1986)
2. J. Zhong, J. Yan, RSC Adv. 6, 1103 (2016)
3. Y. Martin, H.K. Wickramasinghe, Appl. Phys. Lett. 50, 1455 (1987)
4. Y. Martin, C.C. Williams, H.K. Wickramasinghe, J. Appl. Phys. 61, 4723 (1987)
5. J.J. Sáenz et al., J. Appl. Phys. 62, 4293 (1987)