The enhanced magnetoelectric effect and piezoelectric properties in the lead-free Bi3.15Nd0.85Ti3O12/La0.7Ca0.3MnO3 nano-multilayers composite thin films

摘要： The lead-free multiferroic nano-multilayers composite thin films were fabricated on basis of ferroelectric (FE) Bi3.15Nd0.85Ti3O12 (BNT) and ferromagnetic (FM) La0.7Ca0.3MnO3 (LCMO) parents with 8 nm/6 nm periodicity, respectively. The crystal structure, switching of polarization, magnetization and temperature dependence of magnetoelectric coupling (ME) effect for the multiferroic BNT/LCMO composite thin films were investigated in detail, respectively. Ferroelectric behavior along with an enhanced remnant polarization (2Pr) of 42 mC/cm2, saturated magnetization around 151 emu/cm3, the enhanced piezoelectric coefficient d33 of 263 pm/V and the enhanced magnetoelectric effect voltage coefficient of 72.1 mV/cm*Oe were obtained. The results show that the lead-free multiferroic films exhibit both good ferroelectric, dielectric and magnetic properties, as well as the enhanced ME effects, indicating that the coupling effects of electric and magnetic field exist in the fabricated Bi3.15Nd0.85Ti3O12/La0.7Ca0.3MnO3 (BNT/LCMO) nano-multilayer thin films, and the strong ME effect originating from the magnetic-mechanical-electric interaction and interface coupling were demonstrated. These results can be particularly important for developing nano-composite multiferroic devices.