Electrical and Magnetic Properties of Pb(Zr,Ti)O$_{3}$/CoFe$_{2}$O$_{4}$ Composite Thin Films

Composite thin films made of ferroelectric and ferromagnetic materials are the potential candidates for sensors, data storage, and transducers due to possible manipulation of magnetic properties by electric field and vice versa. In this work, we have fabricated Pb(Zr,Ti)O$_{3}$--CoFe$_{2}$O$_{4}$ (PZT-CFO) multilayer thin films using pulsed laser deposition on Pt/TiO$_{2}$/SiO$_{2}$/Si substrates at 400 \r{ }C and post annealed at 650\r{ }C using rapid thermal annealing (RTA) process. The X-ray diffraction studies revealed the growth of the perovskite PZT and the spinel CFO in two separated phases in the composite films. The dielectric constant ($\varepsilon _{r})$ of PZT-CFO multilayer showed strong frequency dispersion with an order of magnitude decrease in the frequency range of 1kHz to 1MHz. Similar decrease in $\varepsilon _{r}$ was also observed with decrease of temperature from 300 to 150 K. The remanent polarization (P$_{r})$ of the film (23 $\mu $C/cm$^{2})$ was also reduced to 1 $\mu $C/cm$^{2 }$with decrease in the temperature (at 100 K). The magnetic measurements in the composite thin films showed the saturation magnetization (M$_{s})$ to be 9 emu/cm$^{3}$ at room temperature that increased to 38 emu/cm$^{3}$ at 5 K.