Charge ordering modulations in a Bi_0.4Ca_0.6MnO₃ film with a thickness of 110 nm

The low temperature sample stage in a transmission electron microscope is used to investigate the charge ordering behaviours in a Bi 0.4 Ca 0.6 MnO 3 film with a thickness of 110 nm at 103 K.Six different types of superlattice structures are observed using the selected-area electron diffraction(SAED) technique,while three of them match well with the modulation stripes in high-resolution transmission electron microscopy(HRTEM) images.It is found that the modulation periodicity and direction are completely different in the region close to the Bi 0.4 Ca 0.6 MnO 3 /SrTiO 3 interface from those in the region a little further from the Bi 0.4 Ca 0.6 MnO 3 /SrTiO 3 interface,and the possible reasons for this are discussed.Based on the experimental results,structural models are proposed for these localized modulated structures.     

Charge ordering modulations in a Bi0.4Ca0.6MnO3 film with a thickness of 110 nm

The low temperature sample stage in a transmission electron microscope is used to investigate the charge ordering behaviours in a Bi0.4Ca0.6MnO3 film with a thickness of 110 nm at 103 K. Six different types of superlattice structures are observed using the selected-area electron diffraction （SAED） technique, while three of them match well with the modulation stripes in high-resolution transmission electron microscopy （HRTEM） images. It is found that the modulation periodicity and direction are completely different in the region close to the Bi0.4Ca0.6MnO3/SrTiO3 interface from those in the region a little further from the Bi0.4Ca0.6MnO3/SrTiO3 interface, and the possible reasons for this are discussed. Based on the experimental results, structural models are proposed for these localized modulated structures.     

高分辨率电子能量损失谱在材料科学中的应用

简要介绍了FEI Titan80—300STEM扫描透射电镜中装配的Wien-filter型能量单色器(monochromator).文章特别指出,装配有能量单色器的FEI Titan80—300STEM扫描透射电镜,可以直接给出高能量分辨率（~0.1eV）的电子能量损失谱.利用高分辨电子能量损失谱,在高能损失区,对于K或L能级自然宽度(natural width of energy level)小于0.5eV的元素,可以获得更细致的的近限精细结构（energy-loss near-edge structure）,更有利于解析其电子结构;在低能损失区,可以用于精确地确定半导体材料的带隙（bandgap）以及p型掺杂引起的带隙能的变化.