Evidence of magnetodielectric coupling in bismuth doped lanthanum ferrite obtained by high-energy ball milling

In this study, the effects of Bi³⁺ doping of LaFeO₃ on the crystal structure and the multiferroic properties of La_1−xBi_xFeO₃ (0.0 ≤ x ≤ 0.5, Δx = 0.1) are analyzed. Moreover, the magnetodielectric coupling in these materials is discussed. At low doping levels (x ≤ 0.3 mol), the orthorhombic LaFeO₃ stabilizes, and at high bismuth contents (x ≥ 0.4), the orthorhombic BiFeO₃ is formed, which was confirmed by determining the Néel temperature (623 K–823 K). The magnetic behavior of the samples shows antiferromagnetic order for all compositions. All the samples showed high relative permittivity values, which increased by doping with Bi³⁺. Furthermore, the presence of Bi decreased the dielectric dissipation factor, which is attributed to low-crystal-structure distortion. Finally, magnetodielectric coupling in these multiferroic materials is reported for the first time, as observed through changes in the relative permittivity under different applied fields and frequencies.