Determination of A-site deficiency in lanthanum manganite by XRD intensity ratio

A method based on the X-ray diffraction intensity ratio was developed to determine the maximum deficiency that the perovskite-structured La1−xMnO3±δ can accommodate at the A-site. Computer simulation predicts that the intensity ratio of (024) and (012) reflections for La1−xMnO3±δ in hexagonal setting increases with increasing the La deficiency x. XRD analysis shows that with increasing x until 0.09, the ratio increases as predicted, then levels off with further increase in x. An abrupt change in electrical conductivity is also observed at x of ∼0.10. It is concluded that the maximum deficiency lies in between 0.09 and 0.10 for La1−xMnO3±δ. The methodology presented in this paper in principle can be applied to other perovskite-structured materials.

The X-ray diffraction intensity ratio of (024) and (012) reflections of La1−xMnO3±δI0 2 4/I0 1 2 increases with x until x=0.09 as predicted by the computer simulation, and at x>0.09 the intensity ratio levels off, showing that the maximum lanthanum deficiency is around 0.09.Figure optionsDownload as PowerPoint slide