MAGNETIC PROPERTIES OF THE Fe(PO3)3 METAPHOSPHATE

摘要

The Fe(PO3)3 compound has been synthesized by solid state reaction. The crystal structure consists of a 3-D network, with infinite single bond PO3 single bond infinity chains of single bond PO4 single bond tetrahedra and isolated single bond FeO6 single bond octahedra, where the Fe(III) ions occupy three different crystallographic positions. The ir spectrum of the compound shows bands characteristics of metaphosphate groups with chain structure. The X-band EPR spectra on polycrystalline samples are isotropic with a g value of approximately 2.0, which remains unchanged with variation in temperature. The intensity of the signals increases with decreasing temperature reaching a maximum at about 12 K and at lower temperatures the intensity decreases, becoming silent at 4.2 K. Magnetic measurements at high magnetic fields show a 3-D antiferromagnetic behavior, with a J/k value of -0.36 K. However, the magnetic study at less magnetic fields reveals the existence of a weak ferromagnetism intrinsic to the sample. 22 refs.