Lecturer: Dr. Amit Finkler
Affiliation: University of Stuttgart
Abstract:
We present a novel technique to image
superparamagnetic iron oxide nanoparticles
via their fluctuating magnetic fields. The
detection is based on the nitrogen-vacancy
(NV) color center in diamond, which allows
optically detected magnetic resonance
(ODMR) measurements on its electron spin
structure. In combination with an atomic-
force-microscope, this atomic-sized color
center maps ambient magnetic fields in a
wide frequency range from DC up to several
GHz [1], while retaining a high spatial
resolution in the sub-nanometer range [2].
We demonstrate imaging of single 10 nm
sized magnetite nanoparticles using this spin
noise detection technique. By fitting
simulations (Ornstein-Uhlenbeck process) to
the data, we are able to infer additional
information on such a particle and its
dynamics, like the attempt frequency and the
anisotropy constant [3]. This is of high
interest to the proposed application of
magnetite nanoparticles as an alternative
MRI contrast agent or to the field of
particle-aided tumor hyperthermia.
[1] E. Schäfer-Nolte et al., Phys. Rev. Lett.
113, 217204 (2014)
[2] P. Maletinsky et al., Nat. Nanotech. 7,
320 (2012)
[3] D. Schmid-Lorch et al., Nano Lett. 15,
4942 (2015)