Ferroic states and phase coexistence in BiFeO3-BaTiO3 solid solutions

In this paper structural, electric, magnetic, and Mössbauer spectroscopy studies were conducted in (x)BiFeO3–(1-x)BaTiO3, 0.9 ≥ x ≥ 0.3, solid solutions. X-ray diffraction and Rietveld refinement studies indicated the formation of single-phased materials crystallized in a distorted perovskite structure with the coexistence of rhombohedral and monoclinic symmetries. Room temperature ferroelectric hysteresis loops showed that the electric polarization increases with the increase of the BaTiO3 content due to the singular structural evolution of the studied solid solutions. All samples presented weak ferromagnetic ordering, which indicates that the BaTiO3 substitution in the BiFeO3 matrix released the latent magnetization. Mössbauer studies revealed a magnetic spectral signature corresponding to ordered Fe3+ ions, and a decrease of the magnetic hyperfine magnetic fields with the increase of the BaTiO3 content. The composition 0.3BiFeO3–0.7BaTiO3 presented a spectral signature corresponding to a paramagnetic behavior, which strongly suggests that the observed magnetization in this sample is due to the Ti3+ ions.