Nanodiamonds

Nanodiamonds are diamonds with a size below 1 micrometre. They can be produced by impact events such as an explosion or meteoritic impacts.

A single imperfection can give a nanodiamond an isolated color center, which lets it function as single, trapped atom. Relative to the defect size, they have huge surface areas that allow them to bond with a variety of other materials. Their non-toxicity means that nanodiamonds may be useful in biomedical and mechanical applications.

In 1963, Soviet scientists at the All-Union Research Institute of Technical Physics noticed that nanodiamonds were created by nuclear explosions that used carbon-based trigger explosives.

In 2015 Amanda S. Barnard, Science Leader of Australia’s Office of the Chief Executive (OCE), The Commonwealth Scientific and Industrial Research Organisation (CSIRO), received the Theory Prize at the Foresight Institutes' Feynman Awards. Using theoretical and computational methods, Dr. Barnard increased understanding of the structure and stability of carbon nanostructures and the role that shape plays in establishing properties and interactions under different conditions. The Prize announced focused on Dr. Barnard's work on diamond nanoparticles (nanodiamonds).

The N-V center defect consists of a nitrogen atom in place of a carbon atom next to a vacancy (empty space instead of an atom) within the diamond’s lattice structure.

Applying a microwave pulse to such a defect switches the direction of its electron spin. Applying a series of such pulses (Walsh decoupling sequences) causes them to act as filters. Varying the number of pulses in a series switched the spin direction a different number of times. They efficiently extract spectral coefficients while suppressing decoherence, thus improving sensitivity.Signal-processing techniques were used to reconstruct the entire magnetic field.

The prototype used a 3 mm-diameter square diamond, but the technique can scale down to tens of nanometers.

Nanodiamonds share the hardness and chemical stability of visible-scale diamonds, making them candidates for applications such as polishes and engine oil additives for improved lubrication.

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