Preparation via solid-state reaction at room temperature and characterization of layered nanocrystalline NH4MnPO4·H2O

The layered nanocrystalline NH4MnPO4·H2O was obtained by grinding MnSO4·H2O and (NH4)3PO4·3H2O in the presence of surfactant PEG-400 via a solid-state reaction at room temperature, maintaining the mixture at room temperature for 12 h, washing the mixture with water, and drying at 60 °C. The resulting NH4MnPO4·H2O and its products of thermal decomposition were characterized using thermogravimetry and differential thermal analyses (TG/DTA), IR, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV–vis, and magnetic susceptibility. The data showed that when dried at 60 °C for 5 h, highly crystallized orthorhombic NH4MnPO4·H2O (space group Pmnm(59)) was obtained with an average particle size of 45 nm and an average interlayer distance of 0.8701 nm. On the other hand, monoclinic nanocrystalline Mn2P2O7 with space group C2/m(12) was obtained when the product was calcined at 600 °C for 3 h. Magnetic susceptibility measurements from room temperature to 2.5 K point to ferrimagnetic ordering at TN∼17 K.