Influence of Substrate Thickness on the Electrical Properties of Flexible PbZr0.52Ti0.48O3 Thin Films Grown on Mica

Large-scale PbZr0.52Ti0.48O3 (PZT) thin films with SrRuO3 (SRO) buffer layers were fabricated on flexible mica substrates of various thicknesses by pulsed laser deposition. X-ray diffraction analysis showed that both the PZT ferroelectric films and SRO buffer layers grew epitaxially with (111) preferred orientation. Extensive study of the influence of substrate thickness on the electrical properties of the PZT films revealed that the remanent polarization, piezoelectric coefficient, and dielectric constant all increased consistently with decreasing substrate thickness. This behavior was attributed to the decreased residual strain in the ferroelectric PZT films and clamping effects from the flexible substrate as the substrate became thinner. Ferroelectric property measurements revealed that the PZT thin films on a typical flexible mica substrate with a thickness of 10 μm possessed high mechanical and thermal stability. No obvious deterioration of the electrical performance of the flexible PZT thin films was observed after repeated bending and release for 104 cycles and over a broad temperature range from 20°C to 170°C during bending. These results indicate that flexible PZT thin films show potential for applications in wearable and implantable ferroelectric memory.