The origin of the large magnetoelectric coupling in the ceramic Ba0.1Bi0.9(Ti0.9Zr0.1)0.1Fe0.9O3

Abstract

57Fe Mössbauer spectrometry and x-ray powder diffraction are conducted to examine the structure and the local magnetic order at the level of Fe sites of Ba0.1Bi0.9(Ti0.9Zr0.1)0.1Fe0.9O3 ceramic. The Mössbauer spectra in the temperature range of 77 K–623 K were analyzed using a discrete distribution of hyperfine field, indicating that the Néel temperature T N was about 603 K. The ceramic Ba0.1Bi0.9(Ti0.9Zr0.1)0.1Fe0.9O3 remains stable in the rhombohedral structure (R3c) in the temperature range of 300 K–800 K. The anomaly of volume below T N, as detected from the model Debye–Gruneissen, reveals the presence of magnetoelastic coupling in this compound. The total polarization (P) obtained from Rietveld refined atomic positions is found to depend on the magnetic order that leads to the decrease of the total polarization (P) through the anomaly volume. The reduction in the polarization by ΔP ∼ −2.4 μC cm−2 suggests negative magnetoelectric interaction. The total polarization (P) obtained from Rietveld refined atomic is coupled with the magnetic ordering mediated by magnetoelastic coupling. The hyperfine field (B hf) dependence of polarization (P) at a temperature range below T N exhibits a linear evolution, confirming the linear magnetoelectric coupling. At room temperature, the linear magnetoelectric coefficient is about α ME ≈ 1.84 × 10−9 s m−1.