Room-temperature ferromagnetic properties and Moessbauer investigation of the 0.7FeTiO3-0.3Fe2O3 solid solution

The 0.7FeTiO3-0.3Fe2O3 solid solution were prepared by slow cooling and quenching heat treatments and studied by X-ray diffraction, Moessbauer spectroscopy, and vibrating sample magnetometer (VSM). The crystal structure of samples were found to be rhombohedral structure with the lattice constants of the slow-cooled sample a=5.082 A and c=13.945 A, and those of the quenched sample a=5.085 A and c=13.964 A. Moessbauer spectra of two samples were taken at various temperatures ranging from 4.2 to 400 K and anomalous absorption curves are observed. Moessbauer spectra was fitted to three magnetic components correspond to Fe3+ and Fe2+ in A and B sublattices. At 4.2 K, the magnetic hyperfine fields were Hhf=512, 481, and 309 kA/m for the slow-cooled sample and 512, 479, and 305 kA/m for the quenched sample, respectively. The Moessbauer spectra below the Neel temperature, TN, reveal line broadening accompanying relaxation effects and intensity ratio different from usual powder pattern, indicating preferred spin orientation. The Neel temperature, TN, was determined to be 380 K for the slow-cooled sample and 400 K for the quenched sample. The temperature dependence of the magnetization taken in zero-field-cooling (ZFC) and field-cooling (FC) condition of the slow-cooled and quenched samples exhibits the great irreversibility between ZFC and FC magnetization. Magnetization measurements have shown ferromagnetic hysteresis loops at room temperature