Dielectric and magnetic properties of BiFe1-4x/3TixO3 ceramics with iron vacancies: Experimental and first-principles studies

BiFe1-4x/3TixO3(x = 0-0.2) ceramics with Fe vacancies created by nonstioichiometric compositions were synthesized to study their crystal structures, dielectric, and ferromagnetic behaviors. X-ray diffraction and Raman spectroscopy analysis reveal a structure transition from rhombohedral to orthorhombic phases at x = 0.2. Dielectric measurement shows that the dielectric loss is significantly reduced in the Ti-doped BiFeO3 samples. With increasing x concentration, the remanent magnetization ( M-r) first increases and then decreases. The maximal M-r of 0.13 em mu/g is obtained at x = 0.05. Furthermore, theoretical calculations based on the density-functional theory prove that the Ti-doping does enhance the lattice constants, band gap, and magnetization. These results show that the Ti-doped BiFeO3 with Fe vacancies could enhance resistivity and magnetism, implying a possible improvement in multiferroic behavior. (C) 2013 AIP Publishing LLC.