Double Double to Double Perovskite Transformations in Quaternary Manganese Oxides

Control of cation ordering in ABX3 perovskites is important to structural, physical and chemical properties. Here we show that thermal transformations AA′BB′O6 double perovskites, where both A B sites have 1:1 order, (A0.5A′0.5)2BB′O6 with fully disordered A/A′ cations can be achieved under pressure CaMnMnWO6 SmMnMnTaO6, enabling polymorphs each material recovered. This leads a dramatic switch magnetic properties from ferrimagnetic order perovskite spin glass behaviour the highly frustrated polymorph. Comparison other materials will enable effects disorder on such as ferroelectricity conductivity explored.