Pr0.5Ca0.5Mn0.97Ga0.03O3, a strongly strained system due to the coexistence of two orbital ordered phases at low temperature

摘要

Combining low-temperature electron (ED) and synchrotron powder diffraction (SPD) techniques, we have precisely determined the phase-separated crystal structure of Pr0.5Ca0.5Mn0.97Ga0.03O3. We demonstrate that the phase separation is associated with the onset of charge/orbital ordering at ∼ 230K and that two ordered phases coexist at low temperature. In order to account for the significant anisotropic linewidth broadening observed in the SPD patterns, we had to include a specific strain model in the refinements. One of the phases, the most severely strained, is suggested to result from an imperfect charge ordering. © 2005 Elsevier Inc. All rights reserved.