Structural and Magnetic Properties of ${\rm FeTiTaO}_{6}$

We have investigated the structural and magnetic properties of FeTiTaO₆. From the Rietveid-refined XRD patterns of FeTiTaO₆, its crystal structure at room temperature is determined to be the rutile structure with lattice constants of α₀ = 4.65 Å, and c₀ = 3.02 Å. The c/a ratio of 0.649 is almost same as the value in the parent rutile TiO₂, which is 0.644. Based on the temperature dependence of the susceptibility between 3 and 400 K, measured with superconducting quantum interference device (SQUID), the magnetic Neel temperature (T_N), which is defined as temperature of the maximum slope in dM/dT, is determined to be 40 K. The detailed studies of the local structure have been carried out with ⁵⁷Co Mossbauer spectroscopy at various temperatures. The Mossbauer spectra of FeTiTaO₆ were composed of two six-line hyperfine patterns below 40 K. Also, the magnetic hyperfine field of FeTiTaO₆ is found to be 472 kOe at 4.2 K. The Mossbauer spectra clearly reveal the presence of the magnetic ordering below 40 K in FeTiTaO₆.