Structure and multiferroic properties of ternary (1−x)(0.8BiFeO3-0.2BaTiO3)-xK0.5Na0.5NbO3 (0 ≤ x ≤ 0.5) solid solutions

The ternary (1− x )(0.8BiFeO 3- 0.2BaTiO 3 )- x K 0.5 Na 0.5 NbO 3 (0 ≤  x  ≤ 0.5) solid solutions have been successfully synthesized by a solid-state reaction route. X-ray diffraction and Rietveld refinement studies reveal the phase transition from the rhombohedral and tetragonal phases to the single tetragonal phase with x increasing. The average grain size decreases initially and then increases as x increases, whereas the remnant magnetization shows an opposite trend and reaches the maximum value of ~2.09 emu/g at x  = 0.3. An enhanced remnant polarization of ~8.6 μC/cm 2 appears at x  = 0.3 due to the structure distortion and the decrement of defects. Moreover, the remanent polarization and the relative permittivity reach the maximum value of ~20.14 μC/cm 2 (10 Hz) and ~644 (1 kHz) at x  = 0.5, respectively, and the corresponding dielectric loss decreases to the lowest value of ~0.022 (1 kHz). These results indicate that the properties of ternary BFO-BTO-KNN solid solutions can be modulated by adjusting the K 0.5 Na 0.5 NbO 3 content to adapt to different application needs.