Dielectric Loss of Oxide Single Crystals an Polycrystalline Analogues from 10 K to 300 K

摘要

Measurements of the temperature dependence of microwave dielectric losses in various materials are reported, for temperatures between 20 and 300 K. Both single crystal and polycrystalline TiO_2, LaAlO_3, MgO and Al_2O_3, MgO and al_2O_3 are considered. The temperature dependence of dielectric losses of certain single crystals (MgO and Al_2O_3) are found to be in good agreement with the theory of intrinsic losses for temperatures above 100 K. At lower temperatures losses due to defects and grain boundaries dominate.