Nuclear Magnetic Resonance Imaging with 90 nm Resolution

TL;DR

This paper demonstrates a breakthrough in magnetic resonance imaging by achieving spatial resolution better than 100 nm using magnetic resonance force microscopy, enabling nanoscale imaging of nuclear spins with high sensitivity.

Contribution

The authors developed high-moment magnetic tips and a novel measurement protocol to extend NMR imaging resolution to the nanoscale, surpassing previous limits.

Findings

Achieved 90 nm resolution in NMR imaging.

Detected 19F nuclei in a patterned CaF2 test object.

Demonstrated detection of less than 1200 nuclear spins.

Abstract

Magnetic resonance imaging, based on the manipulation and detection of nuclear spins, is a powerful imaging technique that typically operates on the scale of millimeters to microns. Using magnetic resonance force microscopy, we have demonstrated that magnetic resonance imaging of nuclear spins can be extended to a spatial resolution better than 100 nm. The two-dimensional imaging of 19F nuclei was done on a patterned CaF2 test object, and was enabled by a detection sensitivity of roughly 1200 nuclear spins. To achieve this sensitivity, we developed high-moment magnetic tips that produced field gradients up to 1.4x10^6 T/m, and implemented a measurement protocol based on force-gradient detection of naturally occurring spin fluctuations. The resulting detection volume of less than 650 zl represents 60,000x smaller volume than previous NMR microscopy and demonstrates the feasibility of pushing magnetic resonance imaging into the nanoscale regime.