Electrical Manipulation of Magnetic Anisotropy in a Fe81Ga19/Pb (Mg1/3Nb2/3) O3 - Pb (ZrxTi1-x) O3 Magnetoelectric Multiferroic Composite

Magnetoelectric composites are an important class of multiferroic materials that are paving the way towards a new generation of multifunctional devices directly integrable into data-storage technology and spintronics. This study focuses on strain-mediated electrical manipulation of magnetization in an extrinsic multiferroic. The composite used includes 5- or 60-nm Fe81Ga19 thin films coupled to a piezoelectric (011) Pb(Mg1/3Nb2/3)O3-Pb(ZrxTi1-x)O3 (PMN-PZT) material. A magnetization-reversal study reveals a converse magnetoelectric coefficient αCME,max≈2.7×10-6sm-1 at room temperature. This reported value of αCME is among the highest so far, compared with previous reports on single-phase multiferroics and on composites. An angular dependence of αCME is also shown, arising from the intrinsic magnetic anisotropy of Fe-Ga. The highly efficient magnetoelectric composite Fe-Ga/PMN-PZT demonstrates drastic modifications of the in-plane magnetic anisotropy, with an almost 90∘ rotation of the preferential anisotropy axis in thinner films under an electric field E=10.8kVcm-1. Also, the influence of thermal strain on the bilayer's magnetic coercivity is compared with that for a reference Fe-Ga/glass bilayer at cryogenic temperatures. A different evolution is observed as a function of temperature, revealing a thermomechanical influence of the substrate which has not yet been reported in Fe-Ga thin films coupled to a piezoelectric material.