Shape controllable synthesis of NdFeO3 micro single crystals by a hydrothermal route

Orthorhombic NdFeO3 (space group: Pnma) crystals with controlled morphologies and sizes were synthesized via a hydrothermal method. The morphologies of the final products strongly depend on the concentration of alkali. When the concentration of the KOH solution was adjusted from 16 M to 19 M, cuboid, cross-shaped and bar-shaped NdFeO3 crystals were obtained respectively. The bar-shaped NdFeO3 crystals are preferentially oriented along the direction of [010]. The formation of NdFeO3 crystals can be explained by a dissolution-precipitation mechanism. It is interesting to find that if the precipitates are isolated by centrifugation before hydrothermal treatment, then mixed with KOH solutions, followed by adding an appropriate amount of KNO3, the rod-shaped NdFeO3 crystals with high aspect ratio and small size will be obtained in the hydrothermal route. The magnetic properties of NdFeO3 crystals with different shapes were also explored.