Preparation and multiferroic properties of Bi 0.8La 0.2FeO 3–CoFe 2O 4 ceramics

Abstract

Composite multiferroics usually show larger magnetoelectric effect, which is important for actual application, than their single-phase counterparts. Here, (1− x)BiFeO 3– xCoFe 2O 4 and (1− x)Bi 0.8La 0.2FeO 3– xCoFe 2O 4 ( x = 0.1 , 0.2, and 0.3) multiferroic composite ceramics were prepared. The former system shows low resistivity, which prevents the intrinsic ferroelectric measurements, whereas for the later system, the composition with x = 0.1 shows well saturated polarization–electric field hysteresis loop at room temperature, the measured remnant polarization is 13.4 μC/cm 2. However, for the compositions with x = 0.2 and 0.3, the measured loops show negative curvature near saturation, which is attributed to the decreased resistivity. Further magnetic measurements reveal that at low temperature, 0.9Bi 0.8La 0.2FeO 3−0.1CoFe 2O 4 shows ferromagnetic nature whereas at high temperature antiferroelectric-like nature, which is discussed based on comparing its magnetic response with that of pure Bi 0.8La 0.2FeO 3 and CoFe 2O 4 ceramics. These results may be helpful for further understanding, and designing, new multiferroic composites.