Enhanced magnetodielectric behaviors at wide frequency range and high breakdown strength in BiFeO₃–LaAlO₃ ceramics

(1 −  x)BiFeO₃–xLaAlO₃ [(1 −  x)BFO–xLA] ceramics were synthesized by a conventional solid-state method. XRD and Raman results revealed a series of structural transitions R3c →  R3m (x = 0.1). The grain size can be decreased to ~ 1 μm by LA addition. With increasing contents of LA, maximum magnetization was enhanced monotonically by the composition-driven lattice distortion. Furthermore, the ceramics 0.90BFO–0.1LA in this work showed improved ferroelectricity, decreased leakage current density and had a high breakdown strength of 260 kV/cm at the same time. On one hand, a maximum magnetodielectric coefficient (MC, α_MD) of 3.59% was achieved in 0.80BFO–0.20LA sample. On the other hand, the x = 0.1 sample showed a high α_MD of 1.4% (± 10%) at a wide frequency range of 0.7–300 kHz. These results demonstrated the BFO–LA ceramics can be a superior magnetic field sensing material.