Giant magnetoelectric effects in multilayered composites of cobalt ferrite and lead magnesium niobate titanate

Abstract

The magnetoelectric (ME) coupling responses of [CoFe2O4/(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]n, represented as (CFO/PMNT)n, multilayered composites were theoretically investigated by using an average method. It is found that a stronger interface coupling could be obtained in multilayers than in bilayers if the number of layers (n) is reasonably increased. Using an empirical dependence of the interface coupling parameter on the number of layers n, it is theoretically estimated that the ME coupling effect is first enhanced and then deteriorated with the gradual increase in n. The best ME response is estimated to occur at n=15, where the transverse ME voltage coefficient αE,31 reaches as high as 658 mV·cm−1·Oe−1. Moreover, it is theoretically found that the ME coupling effect in (CFO/PMNT)n multilayered composites is strongly dependent on the volume fraction of the piezoelectric (or magnetostrictive) phase, and the ME voltage coefficient for transverse field orientation (αE,31) is estimated to be roughly 90% higher than that for the longitudinal case (αE,33), revealing a large anisotropy in the ME coupling effect of (CFO/PMNT)n multilayered composites. These findings pave the way for experimental achievement of strong ME coupling responses, and provide important implications for the design and performance optimization of related devices comprising this kind of multiferroic magnetoelectric materials.