Evidence of Magnetoelectric coupling in Bi2(1-x)Ho2xFe4O9 (x=0, 0.01) multiferroic ceramics

Abstract

We report structural, magnetic, dielectric and magnetoelectric properties of orthorhombic Bi_2(1-x)Ho_2xFe₄O₉ (x=0, 0.01) ceramics (space group ‘Pbam’) synthesized by conventional solid state reaction route. Rietveld refined X-ray diffraction (XRD) shows phase formation of the samples along with reduction in lattice parameters and cell volume due to lower ionic radii substitution of Ho³⁺ at Bi³⁺-site. DC magnetization study revealed antiferromagnetic transition (TN) of the parent (BFO = 250 K) as well as 1% Ho substituted sample (BHFO1 = 253 K) along with increase in magnetization. Opening of hysteresis was observed for BHFO1 sample implying onset of weak ferromagnetism with dominating antiferromagnetic behaviour. Moreover, temperature dependent dielectric (ε') study and its derivative (dε'/dT) for both the samples show significant anomaly around the antiferromagnetic transition (T_N) thus, implying a plausible magnetoelectric coupling between the magnetic as well as the electric order parameters in the studied samples. Magnetoelectric coupling was also confirmed from temperature and magnetic field (1.3 T) dependant tan loss plots.