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

Abstract

The dielectric constants (κ′) 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: κ′(Dy3Al5O12)=11.07±0.05; κ′(Ho3Ga5O12) =12.38±0.05; κ′(Dy3Ga5O12)=12.36±0.06; κ′(Tb3Ga5O12) =12.40 ±0.03; κ′(Gd3Ga5O12) =12.18±0.10; κ′(Eu3Ga5O12) =12.46±0.05; κ′(Sm3Ga5O12) =12.55±0.03; κ′(Nd3Ga5O12) =12.59±0.12; κ′(Y3Sc2Ga3O12) =12.94±0.03; κ′(Sm3Sc2Ga3O12) =13.67±0.04; and κ′(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 αD(mineral) =ΣαD (oxides) for six aluminum garnets and twelve gallium garnets is ∼1%.