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用单能慢正电子束 ,测量了不同氧分压下生长的La0 .7Sr0 .3MnO3外延膜的S参数与入射正电子能量E的关系 .结果发现La0 .7Sr0 .3MnO3外延膜中S参数与氧分压是非单调变化的 ;这与沉积氧分压的两种作用相关联的 .在氧分压较高的LSMO薄膜中 ,空位浓度的增加主要是由沉积原子 (离子 )与氧原子碰撞几率增大 ,使其缺乏足够的动能去填补空位引起的 ;在低氧分压的LSMO薄膜中 ,空位浓度的增大则主要是提供成膜所需要的氧原子缺乏 ,从而导致氧空位及其相关缺陷增加
The relationship between the S parameter and the incident positron energy E of La0.7Sr0.3MnO3 epitaxial films grown under different partial pressures of oxygen was measured with a single slow slow positron beam The partial pressure is non-monotonically changing, which is related to the two effects of partial pressure of oxygen deposition. In LSMO films with higher partial pressure of oxygen, the increase of vacancy concentration is mainly caused by the collision probability between the deposition atoms (ions) and oxygen atoms In the LSMO film with low oxygen partial pressure, the increase of the vacancy concentration is mainly to provide oxygen atom deficiency needed for film formation, resulting in oxygen vacancy and related defects increase