Structural, magnetic and dielectric properties of Bi1−ySryFe(1−y)(1−x)Sc(1−y)xTiyO3 (x=0–0.2, y=0.1–0.3) ceramics

Abstract

Bi 1− y Sr y Fe (1− y )(1− x ) Sc (1− y ) x Ti y O 3 ( x = 0–0.2, y = 0.1–0.3) ceramics were obtained by solid-state reaction method. Addition of scandium could simultaneously reduce magnetic coercive field and enhance dielectric properties of prepared samples. ▶ The electrical resistivity of BiFeO 3 is enhanced by forming solid solution with SrTiO 3 . ▶ We further replace Fe 3+ by Sc 3+ in solid solution to reduce H c and achieve a soft magnet. ▶ Structure–magnetic property relationship has been established by Rietveld refinement . ▶ Sc 3+ substitution can inhibit the dielectric loss effectively. In this study, bulk ceramics with general formula Bi 1− y Sr y Fe (1− y )(1− x ) Sc (1− y ) x Ti y O 3 ( x = 0–0.2, y = 0.1–0.3 mol%) were prepared by traditional solid-state reaction method. As a comparison, bulk BiFeO 3 (BF) was also sintered by rapid sintering method. Their structural, magnetic, dielectric properties were investigated. X-ray diffraction analysis indicated that apart from a small amount of secondary phase detected in BF, all other samples crystallized in pure perovskite structure and maintained original R3c space group. The room temperature M – H curves were obtained. While BF had a coercive magnetic field ( H c ) of 150 Oe, Bi 1− y Sr y Fe 1− y Ti y O 3 solid solutions had a much larger value (for y = 0.1, 0.2, 0.3, H c were 4537, 5230 and 3578 Oe, respectively). Sc 3+ substitution decreased the H c values of these solid solutions remarkably, and resulted in soft magnetic properties, as well as a decrease of the dielectric loss. At 1 MHz, the tan δ of Bi 0.7 Sr 0.3 Fe 0.7(1− x ) Sc 0.7 x Ti 0.3 O 3 with x = 0.05, 0.1, 0.15, 0.2 were 0.1545, 0.1078, 0.1046 and 0.1701, respectively.