Magnetic properties of a novel compound 5BaO:4Fe2O3

Magnetic properties of a novel 5BaO-4Fe₂O₃ compound synthesized by a hydrothermal method were studied. The crystal was identified to be hexagonal. The lattice parameters c and a were calculated to be 2.0564 nm and 0.90562 nm, respectively, with a c/a ratio of 2.2707, and the theoretical density was calculated to be 4.802 g/cm³. The saturation magnetization at 0 K is 33.3 emu/g. The Curie temperature is 232°C. The coercivity of the as-prepared particulates is 540 Oe, and becomes 1160 Oe after annealing at 400°C, at which a phase change might have occurred. The particulate starts to transform into BaO-Fe₂O ₃ at above 500°C and loses its magnetization. At least two lattice sites are occupied by ferric ions as revealed by Mossbauer spectroscopy