NMR of23Na in small particles of ferroelectric NaNO2

Pulse and wide line NMR spectroscopy were applied to small ferroelectric NaNO₂ particles, produced from aqueous solution and embedded loosely in silicagel. Mean particle diameters as determined by SEM and TEM were between 0.2 and 5.0 µm. From the cw-experiments it followed, that the particles had the crystalline structure of the bulk. It is shown that the spectrum of critical fluctuations and the phase transition temperature in the particles proved to be independent of the size. If there is a dead layer at the particle surfaces its thickness does not exceed 1×10^–2µm.