Effect of gradient composite structure in cofired bilayer composites of Pb(Zr0.56Ti0.44)O3–Ni0.6Zn0.2Cu0.2Fe2O4 system on magnetoelectric coefficient

This study investigates the ferroelectric, ferromagnetic, and magnetoelectric properties of the cofired bilayer composites consisting of piezoelectric phase with formulation 0.9 Pb(Zr0.56Ti0.44)O3–0.1 Pb[(Zn0.8/3Ni0.2/3) Nb2/3] ? 2 (mol%) MnO2 and 40 mol% ferrite phase with formulation Ni0.6Zn0.2Cu0.2Fe2O4 (NCZF). A bulk composite of the same composition was also synthesized for comparison. Scanning electron microscope (SEM) investigation using quadrant back scattering detector (QBSD) shows migration of ferrite phases through the interface and energy dispersive X-ray spectroscopy (EDX) analysis with X-ray mapping clarifying these as Cu-rich phases. Improved piezoelectric (d33 * 80 pC/N), ferroelectric (polarization of 60 lC/cm2 and 0.1% strain), higher magnetization (25 emu/g) and lower coercive field (2.8 Oe) were recorded for bilayer composite. The results indicate that the gradient bilayer composites with tailored composition such that the fraction of the secondary phase is higher may lead to better magnetoelectric material.