La2/3Sr1/3MnO3薄膜中反相畴界面的原子结构和成分研究

Atomic structure and chemistry of anti-phase boundaries in La2/3 Sr1/3 MnO3 films

本文采用脉冲激光沉积(pulsed laser deposition, PLD)方法在LaAlO3单晶衬底上外延生长了La2/3Sr1/3MnO3薄膜。利用像差校正扫描透射成像(STEM)和原子分辨率的电子能量损失谱(electron energy-loss spectroscopy, EELS),对薄膜中出现的反相畴界(anti-phase domain boundary, APB)的原子结构和化学成分信息进行了表征。结果表明,该薄膜中存在{100}和{100}+{110}两种不同类型的反相畴界,且反相界面处存在Mn离子价态的变化。本文旨在为理解缺陷结构对LSMO磁性和输运性能的影响提供指导信息。

Epitaxial La2/3 Sr1/3 MnO3 films were grown on LaAlO3(001)substrates by pulsed laser deposition(PLD).Atomic structure and chemistry of anti-phase boundaries(APB)in the films were investigated by aberration-corrected scanning transmission electron microscopy(STEM)combining atomic-resolution electron energy-loss spectroscopy(EELS).It is demonstrated that two types of APBs existed in the films—one is the APB on{100}planes and the other type is the APB on both{100}and{110}planes.Both of these two types of APB have Mn concentrations and the valence states of Mn ions at both types of APBs are reduced compared with that in the LSMO films.These results are of great importance for understanding the impacts of defects on magnetic and electronic transport properties of LSMO.