Structure and polytypic faults in Ba4NdMn3O12 compound

We have studied the structure and polytypic defect formation in the 12R perovskite-type Ba4NdMn3O12 compound. Its structure was characterized using transmission electron microscopy (TEM). Like in the 12R ordered oxides of Ba4CeMn3O12 and Ba4PrMn3O12 (Fuentes et al., J. Solid State Chem. 177 (2004) 714), a cationic ordering between Nd and Mn is also expected to be established in Ba4NdMn3O12 with the Nd ions located in the cornersharing octahedra and the Mn ions located in the facesharing octahedra. We also observed in the Ba4NdMn3O12 phase two types of polytypic faults, i.e., the extrinsic hexagonal- type fault with the stacking sequence …cchhhcc… and the extrinsic cubic-type fault with the stacking sequence …hhccchh….