Three Perovskite Phases with Different Cation Orders in Sm₂MnMn(Mn4−xSbx)O₁₂

Cation order, which can be controlled by synthesis conditions and stoichiometry, plays an important role in properties of perovskite materials. Here we show that aliovalent doping by Sb 5+ in Sm 2 MnMn(Mn 4− x Sb x )O 12 quadruple perovskite solid solutions can control cation orders in both A and B sites. Samples with 0.4≤ x ≤2 were synthesized by a high‐pressure, high‐temperature method at 6 GPa and 1770 K. Three regions with different cation orders were found at 0.5≤ x ≤1.0, x =1.5–1.6, and x =1.8. The 0.5≤ x ≤1.0 compositions have a B‐site‐disordered and A‐site columnar‐ordered structure with space group P 4 2 / nmc ; the x =1.5 and 1.6 samples have a B‐site rock‐salt‐ordered and A‐site columnar‐ordered structure with space group P 4 2 / n ; the x =1.8 sample has a B‐site rock‐salt‐ordered and A‐site‐disordered structure with space group P 2 1 / n . All the samples show one ferrimagnetic transition: T C increases from 35 K to 73 K for 0.5≤ x ≤1.0, T C =81 K for x =1.5 and 1.6, and T C =53 K for x =1.8.