Boundary structural transition and grain growth behavior in BaTiO3 with Nd2O3 doping and oxygen partial pressure change Original Research Article

The structural transition of grain boundaries in BaTiO3 and related grain growth behavior have been investigated with changing Nd2O3 dopant concentration and oxygen partial pressure. A correlation among total vacancy concentration, grain boundary structure and grain growth behavior was found. When the total vacancy concentration was low by any means, grain boundaries were well faceted and abnormal grain growth occurred in the presence of {1 1 1} double twins. However, as the total vacancy concentration increased, the fraction of faceted grain boundary gradually decreased and the formation of {1 1 1} twins was suppressed. Further increase in the total vacancy concentration resulted in a change in grain boundary structure from faceted to rough and suppression of abnormal grain growth. These observed changes in grain growth behavior, including a grain growth anomaly with donor doping, can therefore be attributed to a change in boundary mobility with grain boundary structure, which was governed by the total vacancy concentration.