钇铌复合掺杂钛酸锶钡陶瓷的介电和铁电性能研究

Dielectric and ferroelectric characteristics of Ba_(1-x)Sr_xTiO_3 ceramics co-doped with Y_2O_3 and Nb_2O_5

采用固相法制备4种不同Nb2O5与Y2O3比例的钛酸锶钡(Ba0.9Sr0.1TiO3)铁电陶瓷,掺杂总量在0.3%摩尔分数以内.XRD结果显示,Nb5+和Y3+的掺杂均在Ti位形成了替位式共溶.在-50～150℃温度范围内测试的介电结果表明,介电常数的峰值均保持在80℃.当Y2O3大于Nb2O5的含量时,Nb能够增大Y的作用,使BST陶瓷样品具有更大的介电常数、频率色散和铁电相的温度稳定性;当Y2O3小于Nb2O5的含量时,损耗峰向高温移动,介电损耗不断减小,特别是对高频损耗有明显的抑制作用.电滞回线测试表明,Nb2O5大于Y2O3含量的共掺,使BST陶瓷具有更强的铁电性.

Four kinds of bar-strontium titanate(Ba0.9Sr0.1 TiO3) ferroelectric ceramic samples,with the total co-doping amount under 0.3%(mol) of Nb2O5 and Y2O3,were prepared in solid phase method.The XRD results showed that Nb5+ ions and Y3+ ions both occupied Ti-site together to form a substitutional structure.The dielectric test results showed that the peaks of dielectric constant of four samples maintained at 80 ℃ in the test range of-50~150 ℃.It was found that Nb enhances the dielectric effect of Y when the content of Y2O3 was greater than that of Nb2O5 in the sample.As a result the ceramic samples of BST,with greater dielectric constant and higher frequency dispersion,presented the temperature-stability in the ferroelectric phase.When the content of Y2O3 was less than the content of Nb2O5 in the samples,the dielectric loss decreased,and dielectric loss peaks moved to higher temperature.Especially,the high-frequency loss would be inhibited significantly.At last,hysteresis loop tests showed that BST ferroelectric ceramic sample with Y2O3 and Nb2O5,Nb2O5 greater than Y2O3 in content,presented a stronger ferroelectric character.