Exploration of near room temperature magnetoelectric coupling in BaFe10Sc2O19:KNbO3 composite

Abstract

The consequential experimental endeavour has been undertaken to investigate and control the strain-mediated coupling of the magnetic and electric properties of the composite systems composed of Sc-doped BaFe₁₂O₁₉ and KNbO${}_3$. A distinct non-disperse ferroelectric-like anomaly is observed T${}_{kink}$ $\sim$ 265 K, which concomitantly coincides with the magnetic T${}_{cone}$ transition. The observation of external magnetic field dependence dielectric response shows a noticeable decrease in permittivity values, indicating a negative magnetodielectric response. The maximum intrinsic magnetodielectric response is seen in the vicinity of room temperature with the magnetodielectric ratio of 5.4% @ 1 kHz. The linearity of $-\Delta {\varepsilon }^{\prime }\left(H\right)\text{\%}$ vs. M${}^2$ plot is phenomenologically described with the Ginzburg–Landau theory with the magnetoelectric coupling term $\gamma$P${}^2$M${}^2$. The magnetoelectric coupling relies on strain to induce crystal deformations (flexomagnetoelectric response) on either the ferroelectric phase through magnetostriction or in the magnetic phase through the converse piezoelectric effect. Strain-induced changes in the magnetic as well as dielectric properties of the composites lead to strong magnetoelectric coupling to throw more light exploring a potential candidate for room-temperature multiferroic materials.