Study Of Electric And Photoluminescence Properties Of Eu³⁺ Doped Lead Based Ferroelectric Ceramics

Ferroelectric ceramics have excellent dielectric,piezoelectric,ferroelectric and electrostrictive properties,which make them suitable for electronic devices such as transducers,actuators and sensors.Among them,the binary piezoelectric ceramics Pb(Mg_1/3Nb_2/3)O₃-x Pb Ti O₃(PMN-x PT)ceramics and the ternary piezoelectric ceramics Pb(Mg_1/3Nb_2/3)O₃-Pb Zr_xTi_1-xO₃(PMN-PZ-PT)are the typical representatives of high performance piezoelectric materials,which have been extensively investigated and applied.Known as industrial vitamins,rare earth elements are often used as dopants to improve the properties of materials.In ferroelectric ceramics,the doped rare earth ions combine the electrical and optical properties of ferroelectric ceramics to obtain high performance materials.The main contents of this dissertation include the synthesis of rare earth Eu³⁺doped ternary ceramics 0.38PMN-x PZ-(0.62-x)PT?binary ceramics PMN-28PT and the corresponding undoped rare earth Eu³⁺ceramic samples.The ceramic samples mentioned above are made by high temperature solid state sintering method.After that,the properties of the samples were studied.The pyrochlorite phase was converted into perovskite phase by optimizing the experimental process conditions,and the pure phase ceramic samples were finally obtained,which laid a foundation for the future electrical and optical performance tests.The effects of Eu³⁺doping on the phase structure and microstructure of ferroelectric ceramics were also studied,and the effects of Eu³⁺doping were described.Then,the electrical and optical properties of PMN-28PT:x Eu³⁺(x=0,0.5,1.5,2.5)ceramic samples were studied.The piezoelectric,dielectric and ferroelectric properties of PMN-28PT ceramics were tested in the electrical performance,and the effects of different Eu³⁺doping concentrations on piezoelectric constant d₃₃,dielectric constant?_r,relaxation of dielectric peak,Curie temperature T_c,ferroelectric loops,plane electromechanical coupling coefficient k_pand mechanical quality factor Q_mwere obtained.And the reasons are expounded reasonably.In terms of optical properties,the rare earth Eu³⁺doped samples were excited by the specific laser device to obtain the emission spectrums of the ceramic samples.By comparing with the characteristic emission spectrum of Eu³⁺,the optical properties of the doped ceramics were analyzed.Finally,we measured the electrical and optical properties of0.38PMN-x PZ-(0.62-x)PT and 0.38PMN-x PZ-(0.62-x)PT:2.5Eu³⁺.In the electrical aspect,piezoelectric properties,dielectric properties and ferroelectric properties were also tested.We obtained the relevant electrical constants of ceramic samples and the influence of rare earth Eu³⁺doping on the electrical properties of ceramics.The morphotropic phase boundary of 0.38PMN-x PZ-(0.62-x)PT and0.38PMN-x PZ-(0.62-x)PT:2.5Eu³⁺ceramic samples were obtained by combining X-ray diffraction patterns.In the optical study of ternary PMN-PZ-PT ceramics,we also used the laser device to test the emission spectrum of ceramic samples,rare earth Eu³⁺showed a characteristic peak in the ternary lead-based ceramics.By analyzing the emission intensity ratio of Eu³⁺electric dipole transition and magnetic dipole transition,we discussed the relationship between the emission intensity ratio and the change of ceramic component x,which is related to the transformation of ceramic component from tetragonal phase to pseudo-cubic phase.In this dissertation,the electrical properties of ferroelectric ceramics are greatly improved by doping Eu³⁺,and the luminescence information of doped ceramics is studied by the optical properties of rare earth Eu³⁺.The combination of electrical and optical properties lays a foundation for the research of new optical and electromechanical functional materials.