Scanning nano-spin ensemble microscope for nanoscale magnetic and thermal imaging

TL;DR

This paper introduces a nano-spin ensemble scanning microscope that enables rapid, high-resolution magnetic and thermal imaging at the nanoscale, overcoming previous limitations of long acquisition times and lack of topographic data.

Contribution

It presents a novel nano-spin ensemble probe that improves acquisition speed and provides simultaneous topographic, magnetic, and thermal imaging capabilities.

Findings

Achieved up to tenfold faster imaging times.

Resolved nanoscale magnetic fluctuations and static fields.

Mapped laser-induced heating of a single gold nanoparticle.

Abstract

Quantum sensors based on solid-state spins provide tremendous opportunities in a wide range of fields from basic physics and chemistry to biomedical imaging. However, integrating them into a scanning probe microscope to enable practical, nanoscale quantum imaging is a highly challenging task. Recently, the use of single spins in diamond in conjunction with atomic force microscopy techniques has allowed significant progress towards this goal, but generalisation of this approach has so far been impeded by long acquisition times or by the absence of simultaneous topographic information. Here we report on a scanning quantum probe microscope which solves both issues, by employing a nano-spin ensemble hosted in a nanodiamond. This approach provides up to an order of magnitude gain in acquisition time, whilst preserving sub-100 nm spatial resolution both for the quantum sensor and topographic images. We demonstrate two applications of this microscope. We first image nanoscale clusters of maghemite particles through both spin resonance spectroscopy and spin relaxometry, under ambient conditions. Our images reveal fast magnetic field fluctuations in addition to a static component, indicating the presence of both superparamagnetic and ferromagnetic particles. We next demonstrate a new imaging modality where the nano-spin ensemble is used as a thermometer. We use this technique to map the photo-induced heating generated by laser irradiation of a single gold nanoparticle in a fluid environment. This work paves the way towards new applications of quantum probe microscopy such as thermal/magnetic imaging of operating microelectronic devices and magnetic detection of ion channels in cell membranes.