Synthesis of colloidal MnAsxSb1−x nanoparticles: compositional inhomogeneity and magnetic consequences

The ternary manganese pnictide phases, MnAs1−xSbx, are of interest for magnetic refrigeration and waste heat recovery due to their magnetocaloric properties, maximized at the Curie temperature (TC), which varies from 580–240 K, depending on composition. Nanoparticles potentially enable application in microelectronics (cooling) or graded composites that can operate over a wide temperature range, but manganese pnictides are synthetically challenging to realize as discrete nanoparticles and their fundamental magnetic properties have not been extensively studied. Accordingly, colloidal synthesis methods were employed to target discrete MnAsxSb1−x nanoparticles (x = 0.1–0.9) by arrested precipitation reactions of Mn2(CO)10 with (C6H5)3As=O and (C6H5)3Sb in coordinating solvents. The MnAsxSb1−x particles are spherical in morphology with average diameters 10–13 nm (standard deviations