Nanometer-sized crystalline platinum particles have been studied by Pt195 nuclear magnetic-resonance techniques after their removal from a silica support. The spectra show very well-resolved bulk and surface resonance peaks in contrast to supported particles of similar size. Evidence for restricted surface spin diffusion was found from spin-spin relaxation measurements performed on the surface peak. The length scale of the restriction was found to be about 10 possibly associated with surface irregularities. The nuclear-spin diffusion process can be attributed to the Ruderman-Kittel-Kasuya-Yosida indirect exchange coupling between surface Pt atoms the strength of which was found to be the same as that in bulk platinum.
ASJC Scopus subject areas
- Condensed Matter Physics