Effect Of Dopants On Dielectric Properties Of LiTaO₃-based Ceramics

The various properties of lithium tantalate?LiTaO₃?crystals have received widespread attention from researchers,and there are many studies on their single crystals and thin films.Because LiTaO₃ polycrystalline ceramics have certain difficulty in sintering,the application of LiTaO3 polycrystalline ceramics in the structure and dielectric properties is limited.This article mainly chooses the sintering method to choose pressureless,chooses Bi₂O₃ particles,CoO particles and MnO₂ doping to obtain LiTaO₃ based ceramics,and studies the influence of its dielectric properties by adjusting the doping amount of dopant and controlling the sintering temperature.The results show that when the sintering temperature is 1250?,by preparing LiTaO₃ ceramics?BLT?with Bi₂O₃content of 0.5%,1.5%,2.5%,3.5%,respectively,it can be known that when the Bi₂O₃ doping amount is 2.5wt%,The maximum relative density is76.7%.The dielectric spectrum shows that under certain frequency conditions,with the continuous increase of Bi₂O₃,the dielectric constant has a tendency to increase first and then gradually decrease.The maximum value of the dielectric constant of the 2.5BLT ceramic sample is 80;the dielectric loss first decreases and then continues to increase the phenomenon,2.5BLT is the smallest.The dielectric temperature spectrum shows that the dielectric constant reaches a peak value of 310.5 at 641.5?under the test frequency condition of 10k Hz,and the dielectric loss continues to rise with the continuous increase of temperature.From the structure and performance results of 2.5BLT ceramics prepared by sintering at different sintering temperatures,it can be seen that the relative density of2.5BLT ceramics increases slowly and then decreases continuously with temperature changes.2.5BLT ceramics are most densely sintered at 1250?.Dielectric spectrum analysis shows that at a certain frequency,as the sintering temperature continues to increase,the dielectric constant gradually increases and then decreases.The maximum value of the dielectric constant at 1250? is 68,and the dielectric loss is the smallest.When the sintering temperature is 1250?,by preparing LiTaO₃-based ceramics?CLT?doped with CoO content of 1wt%,3wt%,5wt%and 7wt%,it is known that the relative density is mainly affected by the change of Coions,showing an increase The direction of gradual attenuation after reaching the peak.When the Coion is 5wt%,the relative density is 89.43%at the maximum.Coion has a relatively large effect on the dielectric constant of CLT ceramic samples at room temperature,and its effect on dielectric loss is weaker.The maximum value of the dielectric constant of 5CLT is 524.8,and the minimum dielectric loss is 0.194.The dielectric temperature spectrum shows that the dielectric constant of the CLT ceramic sample has been increasing with the amount of Coion doping.It first reaches the peak value of 3055 and then gradually decay.According to the structure and dielectric properties of 5CLT ceramics prepared at different temperatures,the relative density of the ceramics is accompanied by the influence of temperature.It appears that it first increases to the peak and then gradually decays.The sintering at1250?is the most dense.The dielectric spectrum shows that at a certain frequency,the dielectric constant continues to change due to the sintering temperature,showing a situation where it gradually increases first and then decreases slowly.The peak value of the dielectric constant of 5BLT at 1250?is 543.8,and the minimum dielectric loss is 0.07.Obtained from the dielectric temperature spectrum,the peak value of the dielectric constant of the 5BLT ceramic sample at 1250?is 3059.8 at maximum,and the dielectric loss has been increasing with the change of temperature.When the sintering temperature is 1300?,by preparing LiTaO₃-based ceramics?MLT?doped with 1wt%,3wt%,5wt%and 7wt%components of MnO₂,it can be seen that the relative density is accompanied by the change in the amount of manganese dioxide doped The trend of decline after increase.When MnO₂ is 5wt%,the relative density is at most 91.2%.Doping manganese ions in LiTaO₃ can effectively affect the grain growth,and the grain size increases with the change of MnO₂.The room temperature spectrum shows that with the change of MnO₂,the dielectric constant first increases to the peak and then decreases.At 5 wt%,the peak reaches 14779.52,and the minimum dielectric loss is 0.02.The dielectric temperature spectrum shows that the peak value of the dielectric constant of the 5MLT ceramic sample is 5209.8,and the minimum loss is 2.34.The microstructure and dielectric properties of 5MLT ceramics prepared from different sintering temperature conditions are analyzed.At the sintering temperature of 1250?,5MLT ceramics are the most dense.The dielectric spectrum shows that at a certain frequency,the dielectric constant changes with the sintering temperature,and it tends to increase to the peak first and then gradually decay.The dielectric constant is about 900 at 1250?,and the minimum dielectric loss is 0.167.The dielectric temperature spectrum shows that the maximum value of the dielectric constant of the 5MLT ceramic sample at 1250?is 6397.2,and the maximum value of the dielectric constant of the 5MLT ceramic sample at 1350?is8200.5.The minimum dielectric loss value of the 5MLT ceramic at 1250? is 0.64.