GRAIN GROWTH DEPENDENCE OF MICROSTRUCTURE IN La0.67Ba0.33MnO3+δ OXIDES

Grain growth dependence of microstructure in La2/3Ba1/3MnO3+δ oxides has been studied in detail. The result shows that the crystals grew along three vertical axes with a concentric terrace pattern in the sample sintered at 1673K while the oxides sintered at 1573K grew with a lateral growth manner. However, the concentric terrace growth pattern resulted in twin microstructure in the cooling processing and the lateral growth manner produced non-twin microstrcuture in the oxides at ambient, respectively. It was found that the oxide with twin microstructure has a much higher saturation magnetization than the non-twin oxide. This may be due to the easier alignment of the domains in the twin-grained oxide through the rearrangement of dislocations in twin-boundaries.