The non-rhombohedral low-temperature structure of PMN–10% PT

Abstract

The phase diagram of the Pb(Mg1/3Nb2/3)O3 and PbTiO3 solid solution (PMN-xPT)\nindicates a rhombohedral ground state for x < 0.32. X-ray powder measurements\nby Dkhil et al. show a rhombohedrally split (222) Bragg peak for PMN-10%PT at\n80 K. Remarkably, neutron data taken on a single crystal of the same compound\nwith comparable q-resolution reveal a single resolution-limited (111) peak down\nto 50 K, and thus no rhombohedral distortion. Our results suggest that the\nstructure of the outer layer of these relaxors differs from that of the bulk,\nwhich is nearly cubic, as observed in PZN by Xu et al.\n