Improved microwave dielectric properties of MgAl_(2)O_(4)spinel ceramics through(Li_(1/3)Ti_(2/3))^(3+)doping  

作　　者：李潇 杨习志 赖元明 张芹 李宝阳 戚聪 殷俊 王凡硕 巫崇胜 苏桦 Xiao Li;Xizhi Yang;Yuanming Lai;Qin Zhang;Baoyang Li;Cong Qi;Jun Yin;Fanshuo Wang;Chongsheng Wu;Hua Su(School of Mechanical and Electrical Engineering,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China)

机构地区：[1]School of Mechanical and Electrical Engineering,Chengdu University of Technology,Chengdu 610059,China [2]State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China

出　　处：《Chinese Physics B》2023年第5期668-673,共6页中国物理B（英文版）

基　　金：the Chengdu University of Technology(Grant No.KYQD201907728)。

摘　　要：A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,microstructures,and microwave dielectric properties were investigated.The results of x-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that a single phase of MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with a spinel structure was obtained at x≤0.12,whereas the second phase of MgTi_(2)O_(5)appeared when x>0.12.The cell parameters were obtained by XRD refinement.As the x values increased,the unit cell volume kept expanding.This phenomenon could be attributed to the partial substitution of(Li_(1/3)Ti_(2/3))^(3+)for Al^(3+).Results showed that(Li_(1/3)Ti_(2/3))^(3+)doping into MgAl_(2)O_(4)spinel ceramics effectively reduced the sintering temperature and improved the quality factor(Q_f)values.Good microwave dielectric properties were achieved for a sample at x=0.20 sintering at 1500℃in air for 4 h:dielectric constantε_(r)=8.78,temperature coefficient of resonant frequencyτ_(f)=-85 ppm/℃,and Q_(f)=62300 GHz.The Q_(f)value of the x=0.20 sample was about 2 times higher than that of pure MgAl_(2)O_(4)ceramics(31600 GHz).Thus,MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with excellent microwave dielectric properties can be applied to 5G communications.

关 键 词：microwave dielectric ceramics MgAl_(2)O_(4)ceramic co-substitution MgTi_(2)O_(5) solid solubility limit 

分 类 号：TN015[电子电信—物理电子学] TQ174.1[化学工程—陶瓷工业]