Diamond defect enables magnetic sensing breakthrough

Developed by researchers at MIT in the US the new device is claimed to be 1,000 times more energy-efficient than its predecessors and could, it is claimed, lead to miniaturised, battery-powered devices for medical and materials imaging, contraband detection, and even geological exploration.

Magnetic-field detectors - or magnetometers - are already widely used but existing technologies have drawbacks: some rely on gas-filled chambers; others work only in narrow frequency bands, limiting their utility.

The MIT system owes its advanced performance to the innovative use of synthetic diamonds with nitrogen vacancies (NVs) – a defect resulting from a missing atom in the lattice, adjacent to a nitrogen atom.

Electrons in this vacancy interact with magnetic fields, making them useful for sensing applications. A diamond chip about one-twentieth the size of a thumbnail could contain trillions of nitrogen vacancies, each capable of performing its own magnetic-field measurement. However, aggregating all of these measurements has been a problem.