Direct observation of the near-surface layer in Pb(Mg${}_{1/3}$Nb${}_{2/3}$)O${}_3$ using neutron diffraction

Abstract

Spatially resolved neutron diffraction as a function of crystal depth in Pb(Mg${}_{1/3}$Nb${}_{2/3}$)O${}_3$ reveals the presence of a distinct near-surface region. A dramatic change in both the lattice constant and the Bragg peak intensity as a function of crystal depth is observed to occur in this region over a length scale $\sim$ 100 $\hat{I}¼$m. This confirms a previous assertion, based on a comparison between high-energy x-rays and neutrons, that such a near surface region exists in the relaxors. Consequences to both single crystal and powder diffraction measurements and previous bulk neutron diffraction measurements on large single crystals are discussed.

4 pages, 4 figures