Intrinsic Triple Order in A-site Columnar-Ordered Quadruple Perovskites: Proof of Concept

There is an emerging topic in the science of perovskite materials: A-site columnar-ordered A(2)A'A '' B4O12 quadruple perovskites, which have an intrinsic triple order at the A sites. However, in many examples reported so far, A and A cations are the same, and the intrinsic triple order is hidden. Here, we investigate structural properties of Dy2CuMnMn4O12 (1) and Ho2MnGaMn4O12 (2) by neutron and X-ray powder diffraction and prove the triple order at the A sites. The cation distributions determined are [Ho-2](A)[Mn](A)[Ga0.66Mn0.34](A)[Mn3.66Ga0.34](B)O-12 and [Dy-2](A)[Cu0.73Mn0.27](A)[Mn0.80Dy0.20](A)[Mn1.89Cu0.11](B1)[Mn-2](B2)O-12. There are clear signatures of Jahn-Teller distortions in 1 and 2, and the orbital pattern is combined with an original type of charge ordering in 1. Columnar-ordered quadruple perovskites represent a new playground to study complex interactions between different electronic degrees of freedom. No long-range magnetic order was found in 2 by neutron diffraction, and its magnetic properties in low fields are dominated by an impurity with negative magnetization or magnetization reversal. On the other hand, 1 shows three magnetic transitions at 21, 125, and 160K.