Study of La0.5Sr1.5MnO4 structure distortion and charge disproportion at 120K using resonant multi-beam diffraction
Wen-Chung Liu1*, Yi-Hua Chiu1, Ying-Yu Kung1, Po-Yu Liao1, Chih-Hao Cheng1, Yi-Wei Tsai1, Chia-Hung Chu2, Shih-Lin Chang2
1Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
2National Synchrotron Radiation Research Center, Hsinchu, Taiwan
* presenting author:劉文中,
La0.5Sr1.5MnO4 exhibits structural distortion and charge ordering below 217K. In order to resolve the distortion mode and charge disproportion at different manganese sites, here we applied the resonant multi-beam diffraction technique to study this topic. Surprisingly, according to the intensity distribution of the azimuth rotationa about [3/2 3/2 0] (Renninger scan) of the (0 0 0)/(3/2 3/2 0)/(1 -1 0)/(5/2 1/2 0) OUT four-beam diffraction, the charge disproportion between different manganese sites turned out to be around 0.15 rather than 1 electron. Furthermore, the Renninger scan around the (h/4 h/4 0) as the primary reflection has an Umweganregung-type nature, while the numerical simulation shows that the proposed Jahn-Teller distortion should be of Aulfhellung-type. This result indicates that an adaptation of a suitable distortion model is required.

Keywords: Multi-beam X-ray Diffraction, La0.5Sr1.5MnO4