Synthesis of Ge substituted ilmenite and their magnetic and electronic properties

Ilmenite (FeTiO₃) is an antiferromagnetic insulator with Néel temperature (T_N) of 55 K. The magnetic structure of FeTiO₃ is known to be easily frustrated by cation substitution. In the present study we tried to prepare the Ge-substituted FeTiO₃. The samples were prepared by the conventional solid state reaction technique under the controlled oxygen pressure. Formation of a single phase of FeTi _1-xGe_xO₃ with x=0.01 was confirmed by X-ray diffraction (XRD) method. The Ge-substituted FeTiO₃ had a smaller lattice volume than that of un-doped one. SQUID magnetometer and Mössbauer spectroscopy measurements indicated that the Ge-substitution reduced the T _N slightly. Moreover the magnetic hyperfine fields of Ge-substituted FeTiO₃ seemed to be increased in spite of the decreased magnetic moments.