Microwave dielectric properties of 0.2SrTiO(3)-0.8Ca(0.61)Nd(0.26)Ti(1-x)Al(4x/3)O(3) ceramics

Authors：Qu Jingjing; Liu Fei^*; Yuan Changlai; Liu Xinyu; Chen Guohua

Source：MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS, 2015, 191: 15-20.

DOI：10.1016/j.mseb.2014.10.005

• SrTiO3
• Ca0.61Nd0.26Ti1-xAl4x/3O3
• Tolerance factor
• Oxygen octahedral distortion

The phase structure, microstructure and the dielectric properties of 0.2SrTiO(3)-0.8Ca(0.61)Nd(0.26)Ti(1-x)Al(4x/3)O(3) (0.2 <= x <= 0.5) ceramics sintered at 1420-1580 degrees C with conventional solid-state route had been investigated. It was found that the orthorhombic perovskite phase with a small amount of unknown second phase was obtained in the compositional range of 0.2 <= x <= 0.5. Partial substitution of Ca2+ and Nd3+ by Sr2+ on the A site resulted in a slight increase in the dielectric constant (epsilon(r)) for Ca0.61Nd0.26Ti1-xAl4x/3O3 ceramics. With an increasing of x, the interchange of Ti4+ and Al3+ on the B site caused the increase in quality factor (Q.f). Moreover the temperature coefficient of the resonant frequency (tau(f)) gradually reduced to close to zero with a rise of x from 0.2 to 0.5. And the variation of the tau(f) values with the change of tolerance factor (t) and oxygen octahedral distortion (Delta) was discussed as well. An optimized microwave dielectric properties with epsilon(r)similar to 48.3, Q.f similar to 40,700 GHz (at 4.98 GHz) and tau(f)similar to 3.6 ppm/degrees C could be obtained as x = 0.5 after being sintered at 1520 degrees C for 4 h.

• Institution
  Central South University; Guilin University of Aerospace Technology