DYNAMICAL PROCESS OF DOMAIN PATTERN COARSENING IN FERROELECTRIC SODIUM-NITRITE .1. MICROSCOPIC OBSERVATION

The process of domain pattern coarsening in sodium nitrite has been st udied by microscopic observation. The domain pattern was delineated by rubbing the b-face on deer's buff wetted with ethanol. Starting from a nearly one-dimensional domain pattern whose average domain width is 0.6 mu m, the pattern coarsens initially through nucleation and growth of antistripples, The antistripples are shaped like a dagger elongate d in the b-direction. They are nucleated even between two adjacent wal ls separated as wide as 2 mu m. In the late stage the pattern coarsens through the backward motion of the fronts of wedge-shaped domains whi ch have been formed by combined growth processes of antistripples. The sidewise motion of the planar walls was not observed in either of the initial or late stage. The one-dimensional character of the pattern i s retained throughout the whole coarsening process.