Synthesis, morphology and color tone properties of the lanthanum substituted hematite

The polymeric complex method has been employed to investigate the effects of substitution by lanthanum into hematite powder on structures, morphology and color tone properties. X-ray diffraction measurements evidenced the existence of Fe_{2 - x}La_xO₃ at 1000 °C-1200 °C by shifting peaks to lower angles. At higher temperature, lattice parameters and cell volume were found to expand due to the incorporation of La³⁺ ion into the hematite in the range 301.98-303.87 Å³. Crystalline size decreased when increasing the amount of La³⁺ ion in the reaction process. Suppression of particle growth was observed by the Field Emission Scanning Electron Microscopy studies at higher temperatures. Brighter yellowish-red color than that of pure hematite was obtained and it grew into deeper color tone rapidly by increasing the amount of La³⁺ ion into the hematite.