Large converse magnetoelectric properties without bias in composite of rosen-type piezoelectric transformer and magnetization-graded ferromagnetic material

In this paper, we designed a magnetoelectric composite by bonding the graded-magnetostrictive layers of FeCuNbSiB/FeNi-FACE on the output part of the Rosen-type transformer, in which a much higher self-biased CME coefficient is obtained. Due to the different magnetic characteristics of nanocrystalline foil FeCuNbSiB and FeNi-FACE (such as permeability, saturation magnetization and magnetostriction), the FeCuNbSiB/FeNi-FACE layer exhibits a build-in magnetic bias field. When the ac voltage is applied on the input part of the transformer, a large strain is mechanically transferred to the graded-magnetostrictive layers due to the stress concentration effects at full-wavelength resonance frequency. Therefore, the large strain in the output part of the Rosen-type transformer associated with the build-in magnetic bias field of FeCuNbSiB/FeNi-FACE leads to a large self-biased CME coefficient.