The Band Excitation (BE) technique has provided clues to the origins of unique properties of materials that are rooted in their highly disordered structures.
Co-developed by Oak Ridge National Laboratory (ORNL) and Asylum Research, BE shows the origins of materials such as spin and cluster glasses, phase-separated oxides, polycrystalline ferroelectrics and ferromagnets.
These behaviours influence the scaling properties of the materials, including the thickness of thin films at which improved properties manifest.
'Rayleigh behaviours' have a direct bearing on the properties of nanoscale materials and, eventually, the uniformity of nanoscale devices.
The observations, which were made possible by advances in scanning probe microscopy (SPM) at ORNL's Center for Nanophase Materials Sciences and Asylum Research, may result in the rethinking of 100-year-old theories behind the quanta of nonlinearity and properties of heterogeneous materials.
This work is funded by the Department of Energy's Basic Energy Sciences CNMS user programme.
The principal investigators for the work are Stephen Jesse and Sergei Kalinin of ORNL, and Susan Trolier-McKinstry from Penn State.
The findings were recently published in Proceedings of the National Academy of Sciences (PNAS), 20 April 2010, entitled: 'Collective dynamics underpins Rayleigh behaviour in disordered polycrystalline ferroelectrics.' Kalinin said: 'The nonlinear responses are a ubiquitous aspect of disordered materials that is directly linked to their unique functional properties.' 'Our studies illustrate that the emergence of the nonlinear behaviour is associated with large-scale collective responses, providing new clues to century-old problems,' said Roger Proksch, president of Asylum Research, 'The amazing aspect of BE measurements is that the local nonlinearity is measured quantitatively with less than 10 per cent absolute error in volumes millions of times smaller than those addressable by macroscopic measurements - this is highly unusual for SPM,' he added.
