Two-dimensional nanoscale imaging of gadolinium spins via scanning probe relaxometry with a single spin in diamond

TL;DR

This paper introduces a nanoscale imaging method using a single NV center in diamond to detect gadolinium spins with high spatial resolution, enabling detailed study of individual paramagnetic molecules.

Contribution

The authors demonstrate a novel scanning relaxometry technique that achieves 20 nm resolution for imaging individual gadolinium spins using a single NV center.

Findings

Over two orders of magnitude reduction in NV center's T1 relaxation time.

Spatial resolution of 20 nm in detecting gadolinium spins.

Potential for imaging individual spins on nanostructures or biomolecules.

Abstract

Spin-labeling of molecules with paramagnetic ions is an important approach for determining molecular structure, however current ensemble techniques lack the sensitivity to detect few isolated spins. In this Letter, we demonstrate two-dimensional nanoscale imaging of paramagnetic gadolinium compounds using scanning relaxometry of a single nitrogen vacancy (NV) center in diamond. Gadopentetate dimeglumine attached to an atomic force microscope tip is controllably interacted with and detected by the NV center, by virtue of the fact that the NV exhibits fast relaxation in the fluctuating magnetic field generated by electron spin flips in the gadolinium. Using this technique, we demonstrate a reduction in the $T_1$ relaxation time of the NV center by over two orders of magnitude, probed with a spatial resolution of 20 nm. Our result exhibits the viability of the technique for imaging individual spins attached to complex nanostructures or biomolecules, along with studying the magnetic dynamics of isolated spins.