Spatially resolved detection of complex ferromagnetic dynamics using optically detected NV spins

TL;DR

This paper presents a simple optical method using NV centers in nanodiamonds to spatially resolve and detect a wide range of ferromagnetic excitations, enabling nanoscale spectroscopic studies.

Contribution

It introduces a CW detection scheme with NV centers that provides spatial resolution and broad spectral detection of ferromagnetic dynamics, distinct from traditional ODMR methods.

Findings

Detected propagating spinwaves and multi-domain dynamics

Achieved spatial resolution limited by laser spot size

Demonstrated broad spectrum detection of ferromagnetic excitations

Abstract

We demonstrate optical detection of a broad spectrum of ferromagnetic excitations using nitrogen-vacancy (NV) centers in an ensemble of nanodiamonds. Our recently developed approach exploits a straightforward CW detection scheme using readily available diamond detectors, making it easily implementable. The NV center is a local detector, giving the technique spatial resolution, which here is defined by our laser spot, but in principle can be extended far into the nanoscale. Among the excitations we observe are propagating dipolar and dipolar-exchange spinwaves, as well as dynamics associated with the multi-domain state of the ferromagnet at low fields. These results offer an approach, distinct from commonly used ODMR techniques, for spatially resolved spectroscopic study of magnetization dynamics at the nanoscale.