Crystal structure, magnetic and thermal properties of LaFeTeO6

LaFeTeO6 was prepared by solid state reaction of La2O3, Fe2O3 and TeO2 in 1:1:2 molar ratios and characterized by powder X-ray diffraction, thermogravimetry and magnetometry. The detailed crystal structure analysis was carried out by Rietveld refinement. LaFeTeO6 crystallizes in a trigonal lattice with unit cell parameters: a = 5.2049(1) Å and c = 10.3457(2) Å, V = 242.73(2) Å3. The crystal structure is built from sheets of the edge shared FeO6 and TeO6 octahedra stacked along the c-axis. These sheets are connected together by La3+ ions. Thermogravimetric analysis of the compound showed it to be thermally stable up to 1323 K and continuous loss of TeO2 was observed above 1323 K leading to the formation of LaFeO3. High temperature XRD studies revealed a normal expansion behavior of the compound. Temperature and field dependent magnetization of LaFeTeO6 showed paramagnetic behavior in the temperature range of 3–300 K. The effective magnetic moment per Fe3+ ion (5.14 μB) indicates the high spin d5 state of Fe3+ ion.