Frequency and field dependence of magnetoelectric coupling in multiferroic particulate composites

¹ College of Sciences, China Jiliang University, Hangzhou 310018, P.R. China
² College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, P.R. China
³ Department of Physics, Shanghai University, Shanghai 200444, P.R. China

^a e-mail: zhy7612@shu.edu.cn

Received: 25 March 2011
Revised: 24 August 2011
Accepted: 12 September 2011
Published online: 14 November 2011

Abstract

Measurements are presented of the magnetoelectric (ME) coupling of nontoxic lead-free multiferroic composites 0.4CoFe₂O₄-0.6[0.948(K_0.5Na_0.5)NbO₃-0.052LiSbO₃]. The composites are found to exhibit an interesting dielectric response under a dc magnetic bias field. The positive magnetodielectric behavior and its strong frequency dependence in the composite could be related to magnetoresistance and the Maxwell-Wagner effect. The ME effects are strongly dependent on the driving field frequency and dc magnetic bias field. The frequency and magnetic field dependence of direct and converse ME coefficients are related to the relative dielectric constant and the variation in the piezomagnetic coupling with magnetic field, respectively. In addition, the dependence of direct and converse ME coefficients on frequency and magnetic field is quite similar in this multiferroic particulate composite.