Dielectric constants of yttrium and rare-earth garnets:

The polarizability of gallium oxide and the oxide additivity rule.

R .D. Shannon, M.A. Subramanian

Central Researach and Development Department
E.I. Du Pont de Nemours and Co., Experimental Station
Wilmington, Delzaware 19880-0356, USA

T. H. Allik

Science Applicatins International Corporation
1710 Goodridge Drive, P.O. Box 1303
McLean, Virginia 22102

H. Kimura

National Research Institute for Metals
1-2-1 Sengen, Tsukuba, Ibaraki 305, Japan

M.R. Kokta

Union Carbide Corp.
750 So. 32nd Street, P.O. Box 6381
Washougal, Washington 98671, USA

M.H. Randles

Litton Airtron
P.O. Box 410168, Charlotte, North Carolina 28421-0168, USA

G.R. Rossman

Dividion of Geological and Planetary Sciences
California Institute of Technology
Pasadena, California, 91125-2500, USA



The dielectric constants (k ) 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:

Compound k   Compound k
(Dy3A15O12) 11.07 0.05   (Ho3Ga5O12) 12.38 0.05
(Dy3Ga5O12) 12.36 0.06   (Th3Ga5O12) 12.40 0.03
(Gd3Ga5O12) 12.18 0.10   (Eu3Ga5O12) 12.46 0.05
(Sm3Ga5O12) 12.55 0.03   (Nd3Ga5O12) 12.59 0.12
(Y3Sc2Ga3O12) 12.94 0.03   (Sm3Sc2Ga3O12) 13.67 0.04
(La2.67Lu2.67Ga2.66O12) 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 3. The agreement between measured dielectric polarizabilities as determined from the Clausius-Mosotti equation and those calculated from the sum of oxide polarizabilities according to aD(mineral) = aD(oxides) for six aluminum garnets and twelve gallium garnets is ~1%.

Journal of Applied Physics 67, 3798-3802. (1990)