Conduction electron resonance used to determine size of palladium nanoparticles in proton conducting ceramics.

A technique for determining the size of metallic nanoparticles incorporated into a ceramic is demonstrated using conduction electron paramagnetic resonance (CEPR). The resonances associated with palladium nanoparticles in a perovskite material are identified and studied as a function of temperature. As this line shape changes with temperature, the point at which the skin depth of the palladium is the same as the size of the nanoparticles is clearly identified due to a microwave saturation effect. This allows for a determination of their average size, which, in this case is 75±20nm. This is the first example of CEPR being used to determine metallic nanoparticle size in a technologically relevant, embedded in a non EPR-inert material system.