Magnetic properties of (1 − x)Bi0.5Na0.5TiO3 + xMnTiO3 materials

MnTiO3-doped Bi0.5Na0.5TiO3 materials were fabricated by sol-gel technique. According to X-ray diffraction and Raman scattering analyses, MnTiO3 was suitable to be used as solid solution in Bi0.5Na0.5TiO3 but resulted in distorted structure. The optical band gaps decreased from 3.06 eV for pure Bi0.5Na0.5TiO3 to 1.69 eV for 9 mol% MnTiO3 solid solution in Bi0.5Na0.5TiO3. The magnetic properties of Bi0.5Na0.5TiO3 materials were tuned from ferromagnetism to combination of ferromagnetism and paramagnetic-like property with varying MnTiO3 concentration. The reduction of the optical band gap and the tunable magnetic properties of Bi0.5Na0.5TiO3 materials were due to the random distribution of Mn cation in the host lattice as a function of MnTiO3 amounts. This work provides a new trend of selecting dopants to induce ferromagnetism in lead-free ferroelectric materials.