Enhancement of magnetoelectric properties and coupling coefficient of Co1−xCuxFe2O4/Ba0.8Sr0.2TiO3 composite liquid

Abstract

In this paper, Ba0.8Sr0.2TiO3 and Co1−xCuxFe2O4 (x = 0.1, 0.3, 0.5, 0.7) powders were prepared by sol–gel method and chemical coprecipitation, respectively. Then Co1−xCuxFe2O4/Ba0.8Sr0.2TiO3 composite particles with the weight ratio of 1:1 were distributed into a highly insulated non-polar silicon oil to form composite liquid. Effects of Cu content on the microstructure, magnetic, dielectric, and ferroelectric properties as well as the magnetoelectric coupling effect were studied. The results indicate that with the increase of Cu content, the values of remnant magnetization, saturated magnetization, and coercive field of Co1−xCuxFe2O4/Ba0.8Sr0.2TiO3 composite powders were gradually decreased. The dielectric constant values of both Co1−xCuxFe2O4/Ba0.8Sr0.2TiO3 composite powders and liquid are strongly dependent on the Cu content, which increase first and then decrease with the increase of x, when x = 0.5, the dielectric constant shows the maximum value of 2400 at 2 kHz. With the increase of x, the remnant polarization of Co1−xCuxFe2O4/Ba0.8Sr0.2TiO3 composite liquid gradually increases from 0.5 to 0.025 μC/cm2. At the same time, the magnetoelectric coupling coefficient decreases first and then increase with increasing the concentration of Cu, the maximal value is 88 V/(cm Oe), obtained when x = 0.7. These results show that the magnetoelectric properties of magnetoelectric composite liquid depend heavily on the copper content, and successful preparation of magnetoelectric composite liquid can provide an opportunity to improve the magnetoelectric coupling coefficient of multiferroic materials.