Defective diamond key to nanoscale MRI

Nature : Magnetic resonance imaging (MRI) devices determine the structure of a sample by measuring how its molecules resonate in response to specific wavelengths of electromagnetic radiation. The technique’s spatial resolution is limited, however, by the size of the radiation detector, whose magnetic coils are hard to make smaller than a few micrometers. Now Friedemann Reinhard of the University of Stuttgart in Germany and Daniel Rugar of IBM’s Almaden Research Center in San Jose, California, have each led teams that used defective diamonds to give MRI devices the ability to examine the atomic components of individual molecules. Instead of using a normal diamond with a regular crystal structure, however, both teams created crystals with missing carbon atoms and additional nitrogen atoms. But the teams used the crystals differently. Reinhard’s team placed different samples on the diamonds, measured how nuclear resonance influenced the spin of the electrons in the nitrogen atoms, and found that it was determined by a 5-nm section of the sample. Rugar’s team instead manipulated the electrons of their sample’s hydrogen atoms, which provided more structural information. Reinhard says the next step is to attach the diamond to the tip of a scanning microscope and generate images of the samples.