Enhanced Magnetodielectricity In Gd3+ Substituted Bi2Fe4O9 Ceramics

We report the synthesis of orthorhombic Bi2(1-x)Gd2xFe4Og (x=0, 0.015) ceramics by solid state route and have investigated its structural, magnetic, dielectric and magnetodielectric properties. Rietveld refinement of X-ray diffraction pattern at room temperature shows structural distortion due to lower ionic radii substitution. Magnetic measurements confirmed an enhanced antiferromagnetic transition temperature (T-N) in x = 0.015 (254 K) as compared to the parent sample (250 K) along with an increase in magnetization due to the coupling between Gd3+ and Fe3+ ions. A concomitant anomaly in dielectric (epsilon') and tan loss plot around T-N indicated plausible magnetoelectric coupling (MEC) in both the samples and the MEC coefficient (gamma) is approximated by similar to gamma M-2. The highest value of the magnetodielectric response (similar to 100% enhancement) has been observed for x=0.015 sample.