Dielectric constants of yttrium and rare-earth garnets, the polarizability of gallium oxide, and the oxide additivity rule

Abstract

The dielectric constants (kappa[script ']) and dielectric loss values of 10 rare-earth gallium garnets and 1 rare-earth aluminum garnet were measured at 1 MHz using a two-terminal method with empirically determined edge corrections. The results are: kappa[script '](Dy3Al5O12)=11.07±0.05; kappa[script '](Ho3Ga5O12) =12.38±0.05; kappa[script '](Dy3Ga5O12)=12.36±0.06; kappa[script '](Tb3Ga5O12) =12.40 ±0.03; kappa[script '](Gd3Ga5O12) =12.18±0.10; kappa[script '](Eu3Ga5O12) =12.46±0.05; kappa[script '](Sm3Ga5O12) =12.55±0.03; kappa[script '](Nd3Ga5O12) =12.59±0.12; kappa[script '](Y3Sc2Ga3O12) =12.94±0.03; kappa[script '](Sm3Sc2Ga3O12) =13.67±0.04; and kappa[script '](La2.66Lu2.66Ga2.66O12) =14.40±0.03. The dielectric polarizability of Ga2O3 derived from the dielectric constants of these and other Ga compounds is 8.80±0.14 Å3. The agreement between measured dielectric polarizabilities as determined from the Clausius–Mosotti equation and those calculated from the sum of oxide polarizabilities according to alphaD(mineral) =SigmaalphaD (oxides) for six aluminum garnets and twelve gallium garnets is ~1%.