Probing a spin transfer controlled magnetic nanowire with a single nitrogen-vacancy spin in bulk diamond

TL;DR

This study demonstrates how a single nitrogen-vacancy center in diamond can be used to probe, control, and measure magnetic nanowire dynamics driven by spin transfer torques, revealing magnetic oscillations and cooling effects.

Contribution

It introduces a novel method of using NV centers to directly observe and manipulate spin transfer torque-induced magnetic oscillations in nanowires.

Findings

Detection of large-amplitude magnetic oscillations driven by spin transfer torques.

NV centers can directly induce and control magnetic oscillations.

Observation of magnetic cooling from room temperature to ~150 K.

Abstract

The point-like nature and exquisite magnetic field sensitivity of the nitrogen vacancy (NV) center in diamond can provide information about the inner workings of magnetic nanocircuits in complement with traditional transport techniques. Here we use a single NV in bulk diamond to probe the stray field of a ferromagnetic nanowire controlled by spin transfer (ST) torques. We first report an unambiguous measurement of ST tuned, parametrically driven, large-amplitude magnetic oscillations. At the same time, we demonstrate that such magnetic oscillations alone can directly drive NV spin transitions, providing a potential new means of control. Finally, we use the NV as a local noise thermometer, observing strong ST damping of the stray field noise, consistent with magnetic cooling from room temperature to $\sim$150 K.