Enhancement of Magnetoelectric Effect in Layered Polymer Composites by Zn(2+) and Ni(2+) Substitution in CoFe(2)O(4) Nanoparticles.

Two-layered structures consisting of piezopolymer and magnetic elastomer were investigated as magnetoelectric material. Three types of magnetic elastomer based on cobalt ferrite (CoFe(2)O(4)) and Ni- or Zn-substituted CoFe(2)O(4) nanoparticles were used as magnetically sensitive layers. Cobalt ferrite nanoparticles are considered one of the most promising metal-oxide nanomaterials because of their favorable magnetic properties, such as high saturation magnetization and magnetic anisotropy. The substitution of Co(2+) in cobalt ferrite with other transition metals allows for additional tailoring of these properties. The modified magnetic behavior of the substituted CoFe(2)O(4) nanoparticles directly influenced the magnetic properties of magnetic elastomers and, consequently, the magnetoelectric response of composite structures. In this case, the resonant frequency of the magnetoelectric effect remained largely independent of the type of magnetic nanoparticles in the magnetic elastomer layer but its magnitude increased upon Zn substitution up to ~107 mV·cm(-1)·Oe(-1). These findings highlight the potential of chemically engineered magnetic properties of CoFe(2)O(4) nanoparticles for manufacturing magnetoelectric composites to expand their applications in energy harvesting and sensors.