Dielectric properties of La3Ga5SiO14 at microwave frequencies between 10 and 400 K

We report measurements of dielectric permittivity and dielectric losses at microwave frequencies of lanthanum gallium silicate as a function of temperature. The dielectric rod resonator method was used to evaluate the two relative permittivity tensor components epsilon (t) and epsilon (z) of this uniaxial dielectric crystal. Between 10 and 400 K, epsilon (t) varies from 18.92 to 19.65 whereas epsilon (z) ranges from 60.81 to 46.66. Around 300 K, the temperature coefficients of epsilon (t) and epsilon (z) have opposite signs and are equal to 130 and -720 ppm/K, respectively. This characteristic enables one to design a self-compensated microwave resonator presenting a low frequency temperature sensitivity. For the measured dielectric sample the dielectric losses range from 1x10(-4) to 5x10(-6) between 300 and 20 K and are actually limited by the crystal quality. (C) 2001 American Institute of Physics.