High-precision magnetic field sensing

Researchers have succeeded in measuring tiny changes in strong magnetic fields with unprecedented precision. In their experiments, the scientists magnetized a water droplet inside a magnetic resonance imaging (MRI) scanner, a device that is used for medical imaging. The researchers were able to detect even the tiniest variations of the magnetic field strength within the droplet. These changes were up to a trillion times smaller than the seven tesla field strength of the MRI scanner used in the experiment.

(via WSJ)