The magnetic properties of FeTa2O6. Magnetic structure and low-dimensional behavior

FeTa2O6 was investigated by X-ray and neutron diffraction, magnetic susceptibility, heat capacity, and Mössbauer effect techniques. The tri-rutile structure was confirmed, space group P42mnm. a = 4.749(2) Å, c = 9.192(4) Å and the extent of chemical order between Fe2+ and Ta5+ and Ta5+ was found to be at least 97%. Positional parameters agree well with previous work. A maximum in the magnetic susceptibility versus temperature data occurs at 15(1) K, also in agreement with previous work. Specific heat and neutron diffraction data show that the true Néel temperature for 3-d order is 8.5 K. To explain the high-temperature susceptibility a 2-d Ising model is proposed. A unique solution for the 3-d magnetic structure is found by combining neutron diffraction and Mössbauer effect data.