Fe2P2O7 and Fe2P4O12 studied between 5–800 K

Abstract

Mossbauer spectra of triclinic Fe2P2O7 indicate the existence of two crystallographic metal positions in the structure. In the paramagnetic region the two Mossbauer doublets are closely overlapping. The magnetic transition takes place at ≈ 21 K and the saturated fields are around 12 tesla for the two positions. In monoclinic Fe2P4O12 the two octahedrally coordinated metal positions give quite different quadrupole splittings (1.5 and 3 mm/s at room temperature) and hyperfine field values (42 and 12.5 Tesla at 5 K). The transition temperature is at ≈ 18.5 K.