Studies On Electrical And Spectroscopic Properties Of Lithium Erbium Co-doped Barium Titanate Ceramics

Barium titanate?BaTiO₃?ferroelectric ceramics with perovskite structure are widely studied.They have high dielectric and moderate piezoelectric properties.But the working temperature is narrow,and it is not easy to sinter.Recent research works are mainly to improve the electrical properties by using ion doping and preparation process improving in the barium titanate ceramics.In this dissertation,Li⁺/Er³⁺co-doping is used to improve the electrical and luminescence properties of barium titanate ceramics.The conventional contact method is usually used to characterize the electrical properties of ferroelectric ceramics.In recent years,with the development of fluorescent ferroelectric ceramics,the researchers began to characterize the fluorescent properties of ferroelectric ceramics by establishing the relationship between the fluorescence spectrum and the electrical properties.Compared with the contact measurement method,fluorescence characterization is more convenient and quick.At present,most of the fluorescence characterization methods focus on the temperature sensitivity of ferroelectric ceramics,but little is known about the microstructure of ceramics.In this dissertation,the electrical and spectral properties of the erbium erbium co-doped barium titanate ceramics were studied,and the response relationship between the critical properties of Li⁺/Er³⁺:BaTiO₃ceramics is explored.The electrical properties of Li⁺/Er³⁺:BaTiO₃ ceramics with different proportions were studied.Li⁺/Er³⁺:BaTiO₃ ceramic samples,pure BaTiO₃ ceramic samples,and 1%Er³⁺:BaTiO₃ ceramic samples with different proportions were prepared by the sol-gel method.The ferroelectric and dielectric properties of the samples were measured.It was found that the ferroelectric and dielectric properties of Li⁺/Er³⁺:BaTiO₃ ceramics are higher than those of pure BaTiO₃ ceramics,but lower than 1%Er³⁺:BaTiO₃ ceramics.The relationship between upconversion fluorescence spectra and temperature of Li⁺/Er³⁺:BaTiO₃ ceramics has been studied.The relationship among temperature,microstructures,and up conversion fluorescence spectra is established by measuring the response characteristics of the upconversion fluorescence spectra of different ratio Li⁺/Er³⁺:BaTiO₃ ceramics.The upconversion fluorescence spectra of Li⁺/Er³⁺:BaTiO₃ceramics at different temperatures were studied.It was found that there is a mutation in the upconversion fluorescence spectra at the Curie-Weiss temperature T₀,indicating that the microstructure of Li⁺/Er³⁺:BaTiO₃ ceramics changed near this temperature.The relationship between the infrared fluorescence spectra and the temperature is studied in Li⁺/Er³⁺:BaTiO₃ ceramics.It was found that the efficiency of infrared luminescence is different in different ratio Li⁺/Er³⁺:BaTiO₃ ceramics.The luminescence of 1%Li⁺/Er³⁺:BaTiO₃ ceramic is the strongest one.The temperature response of IR fluorescence spectrum is similar to that of fluorescence spectrum,and there is also a mutation in the IR fluorescence spectra at the Curie-Weiss temperature T₀.