Preparation And Luminescent Properties Of Asite Ion Doped PMN-PT Textured Ceramics

Lead magnesium niobate-lead tieanate[?1-x?Pb(Mg_1/3Nb_2/3)O₃-x Pb Ti O₃,?PMN-x PT?]relaxor ferroelectric materials have high dielectric properties,high piezoelectric properties and excellent electrostrictive properties,showing a wide range of applications in accelerometer,hydrophone,medical ultrasonic transducers and micro-displacement drivers.PMN-PT polycrystalline ceramics is the ABO₃ perovskite phase structure.Since the ion radius of rare earth elements is similar to the A site Pb²⁺ion radius.The incorporation of rare earth elements in the PMN-PT ceramics will not affect the perovskite phase structure,and the piezoelectric properties of the ceramic will be improved by the local heterostructure.The texture of polycrystalline ceramics can improve the grain orientation,thus improving the piezoelectric performance of ceramics.This paper focuses on the preparation and luminescence characteristics of PMN-PT texture ceramics doped with A-site ions:preparation of barium titanate?Ba Ti O₃?templates,preparation of A-site doped PMN-PT textured ceramics.Then,electrical and luminescence properties of the ceramics was investigated.Finally,preparation of the PMN-PT oriented films.First,the precursor Bi₄Ti₃O₁₂ with good surface morphology was prepared by the molten salt method,and a plate-shaped perovskite Ba Ti O₃ template with a size of 10-20?m and a tiickness of 0.5?m was prepared by the topological chemical reaction method.Several acid and deionized water dried to obtain a size of 10-20?m,a sheet had a thickness of 0.5?m Ba Ti O₃template.Then[001]-oriented A-site Sm³⁺doped PMN-PT textured ceramics were prepared by using plate-shaprd Ba Ti O₃ as seed crystal and using template grain growth technology?TGG?.Finally,the formation of prime embryos under different slurry ratios and casting process parameters was studied,a thickness of 50-55?m,spread evenly template biscuit was prepared.A-site Sm³⁺doped PMN-PT textured ceramic was prepared by changing the template content and sintering temperature.Second,electrical properties of the textured ceramics prepared above were tested,and the result showed that:the textured ceramics prepared at 1.5wt%and 1250°C for 20h were grown along the[001]direction..After the sample was polarized at a voltage of 3kv/mm,the piezoelectric constant d₃₃ is 1010p C/N,the residual polarization intensity Pr is 29.1?C/cm²,and the coercive field Ec is 3.44kv/cm.Moreover,the electromechanical coupling coefficient k₃₃ is0.76.The dielectric constant?is 33097,the transition temperature from relaxation phase to ferroelectric phase T_r-t is 47°C,and the Curie temperature T_c is 110°C.Compared with polycrystalline ceramics(d₃₃ is 670p C/N,The phase transition temperature T_r-t is 72°C,and the Curie temperature T_c is 116°C),PMN-PT-Sm textured ceramics can achieve the best dielectric properties in the range of 50-100?Third,the luminescence characteristics test results show that:the A-site Sm³⁺doped PMN-PT textured ceramic has a good transmittance in the visible light range.When the template content is 1.5wt%,the transmittance in the blue-green light band reaches 30%.The light emission of doped textured ceramics is mainly due to the unique 4f layer electron level transition of rare earth elements.Under the excitation of blue light with a wavelength of 406nm,the emission light in the red-orange band is the strongest,under the emission of red light with a wavelength of597nm,because more red-orange light can migrate to the low-energy ground state in the form of radiation,the fluorescence of the ceramics effect conversion rate is high.Fluorescence spectroscopy tests on textured ceramics with different sintering temperatures and holding times found that the fluorescence spectrum reached the strongest when holding at 1250°C for 20 hours.When the sintering temperature is too high,it will reduce the internal crystal phase melting of the ceramic,which will reduce its electrical and luminous performance.Finally,Sm³⁺doped PMN-PT thin films were prepared on the Pt/Ti O₂/Si O₂/Si substrate by the Sol-gel method.It is showed that the PMN-PT-Sm thin films have a pure perovskite phase structure,the degree of orientation in the[001]direction reaches 94%,the surface roughness Ra is 2.49nm,and the surface planeness is fine.Fluorescence spectroscopy tests were performed on the film at different powers.The results showed that when the slit width was 5 nm and the 406nm blue light was excited,the film emitted the strongest light in the red and orange light bands at 563 nm,598 nm,and 630 nm.