

Journal of the Korean Ceramic Society 1997;34(4): 368. 
$(1x)La_{2/3}TiO_3xLaAlO_3$계의 마이크로파 유전 특성 
이경태, 박현수, 문종하 
전남대학교 무기재료공학과 
Microwave Dielectric properties of $(1x)La_{2/3}TiO_3xLaAlO_3$System 





ABSTRACT 
The microwave dielectric properties of (1x)La2/3TiO3xLaAlO3 system in which LaAlO3 having $varepsilon$r$geq$90 and positive $tau$f was investigated. The crystal system of (1x)La2/3TiO3xLaAlO3 was pseudocubic in the range of 0.1$leq$x$leq$0.07. Its lattice constant increased with increasing x in spite that the amount of LaAlO3 containing of smaller Al(0.57 $AA$) ion than Ti(0.64 $AA$) increased. As the amount of LaAlO3 increased from x=0.1 to 0.9, the relative dielectric constant ($varepsilon$r) decreased from 50 to 23 and the temperature coefficient of resonant frequency($tau$f) decreased from +84 to 50. On the other hand, the value of Q.f0 reached a maximum (148,000 at 7 GHz) at x=0.7, where a rapid increase in the peak intensity of XRD occured, and further increased after prolonged sintering. The microwave dielectric properties of $varepsilon$r=37, Q.f0=47,000 (at 7 GHz), and $tau$f=2 ppm/$^{circ}C$ were obtained near 0.6La2/3TiO30.4LaAlO3 (x=0.4) composition. 
Key words:
$(1x)La_{2/3}TiO_3xLaAlO_3$ system, Microwave, Dielectric constant, Unloaded Q, Temperature coefficient of resonant frequency 


