The Synthesis and Characterisation of Ferromagnetic CaMn2O4 Nanowires

The synthesis of marokite CaMn2O4 nanowires using a hydrothermal method is reported. Transmission electron microscopy and electron diffraction measurements show that the nanowires are polycrystalline in nature with diameters between 10 and 20 nm and lengths ranging from approximately 100 to 500 nm. Most interestingly, in contrast with the bulk material, magnetization measurements show that these nanowires exhibit ferromagnetic ordering with a Curie temperature (TC) of approximately 40 K. Ferromagnetism is observed in marokite‐type CaMn2O4 nanowires with diameters between 10 and 20 nm (see transmission electron microscopy image). The structure can be described as MnO6 octahedral units linked to form a manganese oxide framework with the Ca2+ ions occupying tunnels formed within this framework (see picture, where the pink squares are MnO6 octahedra and the yellow spheres are Ca2+ ions).