Structural Phase Diagram of Ca_(1-x)Y_xMnO_3: Characterization of Phases

摘要

To help the understanding of the physical behavior of Ca1_xYxMnOJ, its phase diagram in the whole x concentration c range was investigated taking into account the stability of phases r and the possible coexistence of different structural phases. By careful analysis of powder X-ray diffraction (XRD) patterns, we c were able to observe the following phase diagram: (i) Orthor- e hombic phases were detected both in the region of 0.25 ( (0 type phase with Ca site twelve fold coordinated) and in the ( region of 0.5<= x <= 0.75 (0' type phase with Ca site ninefold . coordinated). (ii) Phase segregation for 0.25 <= x <= 0.5 and for 1. x ~ 0.75 that have not been reported previously, hexagonal r YMn03 segregates as a separate phase for x > 0.75, and for ~ 0.25 <= x <= 0.5 the coexistence of Cao. 75 Y o.25Mn03 ( 0) and c Cao.s Yo.sMnOJ (0') have to be included in the refinement for it to fl converge.