Abstract
(1-x)Bi(0.5)(Na(0.77)K(0.20)Li(0.03))(0.5)TiO(3)-xBi(0.8)Ba(0.2)FeO(3) ((1-x)BNKLT-xBBF) ceramics with x = 0-0.4 were synthesized by the solid-state combustion technique. X-ray diffraction (XRD) analysis confirmed a pure perovskite structure with coexisting rhombohedral and tetragonal phases. Rietveld refinement revealed that the unit cell volume increased with increased x due to the substitution of smaller Bi(3+) and Ti(4+) ions by larger Ba(2+) and Fe(3+) ions at the A- and B-sites, respectively. The average grain size and measured density also increased with increasing x, while the resistivity decreased. At room temperature, (1-x)BNKLT-xBBF ceramics with x = 0.2-0.4 exhibited multiferroic behavior, characterized by ferroelectric and ferromagnetic hysteresis loops. The 0.8BNKLT-0.2BBF ceramic exhibited the most favorable properties, including: the highest relative density (95.48%), the highest dielectric constant and low dielectric loss at room temperature (ε(R) = 1746 and tan δ(R) = 0.0296), good ferroelectric properties (P(r)=6.46 µC/cm(2) and E(c)=11.84 kV/cm) and good ferromagnetic properties (M(r)=0.002 emu/g, H(c)=110 Oe and α(E) = 1.092 mV/Oe·cm). These results indicate that 0.8BNKLT-0.2BBF has the potential for applications in lead-free, room temperature multiferroic applications.