Large electrostrain and high optical temperature sensitivity in BaTiO3-(Na0.5Ho0.5)TiO3 multifunctional ferroelectric ceramics

Abstract

Ferroelectric (1 − x)BaTiO₃-x(Na_0.5Ho_0.5)TiO₃ ceramics with ferroelectric and up-conversion luminescent multifunctions were designed and fabricated by a solid state reaction process. Their structure, ferroelectric, piezoelectric, up-conversion photoluminescence and relative optical temperature sensing properties were investigated systematically. Crystal structure analysis and Rietveld refinements based on the powder X-ray diffraction data show that the ceramics crystallized in the tetragonal perovskite space group P4mm at room temperature. Enhanced electrical properties and strong green up-conversion luminescence with thermally coupled green emission bands centered at 523 and 553 nm were observed. For a typical sample x equals 0.05, a large electrostrain of 0.279% was obtained under a 70 kV cm⁻¹ electric field that is comparable to that of the PZT4. Meanwhile, the excellent optical temperature sensitivity (0.0063 K⁻¹ at 480 K) is higher than that of Er-doped BaTiO₃ nanocrystal materials. The results suggest that the BaTiO₃-(Na_0.5Ho_0.5)TiO₃ material should be an attractive material for piezoelectric actuator and temperature sensing device applications.