Giant magnetoelectric coupling observed at high frequency in NiFe2O4-BaTiO3 particulate composite

Abstract

A giant magnetoelectric voltage coupling coefficient without direct current magnetic field observed in NiFe₂O₄-BaTiO₃ particulate composite is reported. The particulate composite was obtained by combining hydrothermal and sol-gel method, and was studied for their crystallographic structure, morphology, magnetic, dielectric and magnetoelectric properties. Results of Mössbauer spectra demonstrated the presence of interface phase in particulate composite, where the changes of the magnetic properties in composite compared to the pure NiFe₂O₄ also confirmed this. The particulate composite exhibits remarkable magnetoelectric effect through both static measurement and dynamic measurement. The special magnetoelectric property of the particulate composite is beneficial for applications in high frequency devices.

Fig. 1. XRD patterns of samples. Inset is an enlarged view of (311) and (440) diffraction peaks for NFO and PC.

Fig. 2. (a) TEM image of BTO, (b) TEM image of PC (c and d) EDS spectra acquired at positions 1 and 2 in (b).

Fig. 3. ⁵⁷Fe Mössbauer spectra of NFO at (a) RT, (b) 453 K and PC at (c) RT, (d) 453 K.

Fig. 4. (a) The M–H loops for samples; (b) the calculated M–H loops for samples, inset: magnetization versus temperature curve for samples measured at 8000 Oe.

Fig. 5. (a) Temperature dependence of the dielectric constant (ε′) and dielectric loss (tgδ) of PC with a frequency of 100 and 1000 kHz; (b) temperature dependence of χ_AC for NFO and PC.

Fig. 6. (a) RT M–H loop of PC under different E_dc (zero, 2.8 and 5.6 kV cm⁻¹), inset: the partially enlarged M–H loops; (b) the dE of PC as a function of the frequency range is 10⁵ to 10⁷ Hz, upper left inset in (b): the α_E of PC as a function of the frequency range is 10³ to 10⁵ Hz; upper right inset (b): frequency dependence of the dielectric constant of PC.