A team led by America's National Institute of Standards and Technology (NIST) has used a combination of neutron diffraction and photon measurements to discover the unusual electronic properties of silver niobate. [Levin, Phys. Rev. B (2009) 79, 104113]
Silver niobate is a ceramic dielectric, a class of materials used to make capacitors, filters and other components of wireless communications equipment. These materials exhibit very high dielectric constants – a high charge capacity – combined with low power dissipation. However, silver niobate is expensive and the proliferation and miniaturisation of consumer devices provides an incentive to find a cheaper material with equally efficient power storage.
The first step to creating these alternative materials is to fully understand the electronic properties of silver niobate itself. Its properties are temperature dependent, peaking at room temperature and making them suitable for everyday applications. Until the recent work no discernable changes were present in its molecular structure.
“The important changes happen at the nanoscale and can't be detected without specialised techniques and instrumentation,” explains NIST's Dr Igor Levin. “Neutron diffraction at ISIS gave us a vital piece of the puzzle in understanding the delicate interplay between the niobium and oxygen atoms present in the material and how this altered at different temperatures.”
This work complemented other research, as the intensity of beam and angular coverage provided by the Gem instrument at ISIS provided unique information in solving the issue.