The Influence of <scp>CoFe₂O₄</scp>@<scp>SiO₂</scp> Fillers on Magnetoelectric Coupling Effect of a P(<scp>VDF</scp>‐<scp>TrFE</scp>)‐Based Composite

ABSTRACT To improve the strain‐transfer efficiency between the piezoelectric and magnetic phases, and thereby promote the magnetoelectric (ME) coupling effect of the poly (vinylidene fluoride‐trifluoro ethylene) (P(VDF‐TrFE))‐based composite, the core‐shell structured magnetic CoFe 2 O 4 (CFO) @SiO 2 filers are introduced into a piezoelectric P(VDF‐TrFE) film, where the ME coupling behavior is disclosed by the COMSOL multi‐physics finite model. We find that the dielectric properties of CFO@SiO 2 /P(VDF‐TrFE) multiferroic films show good thermal stability ranging from −20°C to 160°C, dependent on the CFO@SiO 2 content. Attractively, the saturation magnetization of the composite film with 7.5 wt% CFO@SiO 2 increased from 5.7 to 8.7 emu/g after polarization under 50 MV/m, attributed to a strong magnetoelectric coupling effect. As such, this polarizing composite film is sensitive to an external magnetic field and inspires an output of 124.5 mV at 24 Oe, showing an ME coefficient of ~261 mV/cm·Oe by calculation. This multiferroic material is promising for its application in magnetically sensitive storage devices.