The quantum dynamic range of room temperature spin imaging

TL;DR

This study demonstrates room-temperature quantum spin imaging of a nanoscale ferromagnetic material using nitrogen vacancy centers, revealing detailed coherent dynamics and a high quantum dynamic range.

Contribution

It introduces a method for pixel-wise quantum dynamic imaging of spins coupled to a van der Waals ferromagnet at room temperature, combining magnetic resonance imaging with quantum modeling.

Findings

Achieved quantum dynamic range over 60 MHz in Ramsey mode.

Mapped coherent spin dynamics with pixel-wise Rabi and Ramsey imaging.

Observed a 70-fold increase in maximum quantum oscillation frequency from Rabi to Ramsey modes.

Abstract

Magnetic resonance imaging of spin systems combines scientific applications in medicine, chemistry and physics. Here, we investigate the pixel-wise coherent quantum dynamics of spins consisting of a 40 by 40 micron sized region of interest implanted with nitrogen vacancy centers (NV) coupled to a nano-magnetic flake of $\mathrm{CrTe_2}$. $\mathrm{CrTe_2}$ is an in-plane van der Waals ferromagnet, which we can probe quantitatively by the NV electron's spin signal even at room temperature. First, we combine the nano-scale sample shapes measured by atomic force microscope with the magnetic resonance imaging data. We then map out the coherent dynamics of the colour centers coupled to the van der Waals ferromagnet using pixel-wise coherent Rabi and Ramsey imaging of the NV sensor layer. Next, we fit the pixel-wise solution of the Hamiltonian to the quantum sensor data. Combining data and model, we can explore the detuning range of the spin oscillation with a quantum dynamic range of over $\left|\Delta_{max}\right|= 60 { }\mathrm{MHz} $ in the Ramsey interferometry mode. Finally, we show the effect of the $\mathrm{CrTe_2}$ van der Waals magnet on the coherence of the NV sensor layer and measure a 70 times increase in the maximum frequency of the quantum oscillation going from the Rabi to the Ramsey imaging mode.