Synthesis, thermal stability and magnetic properties of the Lu1−xLaxMn2O5 solid solution

Polycrystalline samples of the Lu1−xLaxMn2O5 solid solution system were synthesized under moderate conditions for compositions with x up to 0.815. Due to the large difference in ionic size between Lu3+ and La3+, significant changes in lattice parameters and severe lattice strains are present in the solid solution. This in turn leads to the composition dependent thermal stability and magnetic properties. It is found that the solid solution samples with x≤0.487 decompose at a single well defined temperature, while those with x≥0.634 decompose over a temperature range with the formation of intermediate phases. For the samples with x≤0.487, the primary magnetic transition occurs below 40 K, similar to LuMn2O5 and other individual RMn2O5 (R=Bi, Y, and rare earth) compounds. In contrast, a magnetic phase with a ∼200 K onset transition temperature is dominant in the samples with x≥0.634.