RETRACTED: Single-proton spin detection by diamond magnetometry.

Extending magnetic resonance imaging to the atomic scale has been a long-standing aspiration, driven by the prospect of directly mapping atomic positions in molecules with three-dimensional spatial resolution. We report detection of individual, isolated proton spins by a nitrogen-vacancy (NV) center in a diamond chip covered by an inorganic salt. The single-proton identity was confirmed by the Zeeman effect and by a quantum coherent rotation of the weakly coupled nuclear spin.

Investigation of surface magnetic noise by shallow spins in diamond.

We present measurements of spin relaxation times (T1, T1ρ, T2) on very shallow (≲5  nm) nitrogen-vacancy centers in high-purity diamond single crystals. We find a reduction of spin relaxation times up to 30 times compared to bulk values, indicating the presence of ubiquitous magnetic impurities associated with the surface. Our measurements yield a density of 0.

Nitrogen-vacancy centers in diamond: nanoscale sensors for physics and biology.

Crystal defects in diamond have emerged as unique objects for a variety of applications, both because they are very stable and because they have interesting optical properties. Embedded in nanocrystals, they can serve, for example, as robust single-photon sources or as fluorescent biomarkers of unlimited photostability and low cytotoxicity. The most fascinating aspect, however, is the ability of some crystal defects, most prominently the nitrogen-vacancy (NV) center, to locally detect and measure a number of physical quantities, such as magnetic and electric fields.

Negatively charged nitrogen-vacancy centers in a 5 nm thin 12C diamond film.

We report successful introduction of negatively charged nitrogen-vacancy (NV(-)) centers in a 5 nm thin, isotopically enriched ([(12)C] = 99.99%) diamond layer by CVD. The present method allows for the formation of NV(-) in such a thin layer even when the surface is terminated by hydrogen atoms.

Radio-frequency magnetometry using a single electron spin.

We experimentally demonstrate a simple and robust protocol for the detection of weak radio-frequency magnetic fields using a single electron spin in diamond. Our method relies on spin locking, where the Rabi frequency of the spin is adjusted to match the MHz signal frequency. In a proof-of-principle experiment we detect a 7.