Structure,defects,and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9 .33Ti18O54 ceramics

• 作者: Weijia GUO Zhiyu MA Yu LUO Yugu CHEN Zhenxing YUE Longtu LI
• 来源期刊: 先进陶瓷（英文版）
• 年，卷（期）: 2022,（4）
• 所属期刊栏目: Research Article
• 页码范围: 629-640
• 页数: 12页
• 语种: 英文

摘要

Low-loss tungsten-bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation(5G)communication technology.In this work,a novel Al/Nd co-doping method of Ba4Nd9.33Ti18O54(BNT)ceramics with a chemical formula of Ba4Nd9.33+z/3Ti18-zAlzO54(BNT-AN,0≤z≤2)was proposed to improve the dielectric properties through structural and defect modulation.Together with Al-doped ceramics(Ba4Nd9.33Ti18-zAl4z/3O54,BNT-A,0≤z≤2)for comparison,the ceramics were prepared by a solid state method.It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping.As the doping amount z increased,the relative dielectric constant(εr)and the temperature coefficient of resonant frequency(τf)of the ceramics decreased,and the Q×fvalues of the ceramics obviously increased when z≤1.5.Excellent microwave dielectric properties of εr=72.2,Q×f=16,480 GHz,and τf=+14.3 ppm/℃were achieved in BNT-AN ceramics with z=1.25.Raman spectroscopy and thermally stimulated depolarization current(TSDC)technique were firstly combined to analyze the structures and defects in microwave dielectric ceramics.It is shown that the improvement on Q×f values was originated from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies(V?),demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.