|
|||||
|
|
Dielectric constants of tephroite,fayalite and olivine and the oxide additivity rule |
|
| Authors: | R D Shannon M A Subramanian S Hosoya G R Rossman |
| Institution: | 1. Central Research and Development Department, E. L Du Pont de Nemours and Co., Inc., Experimental Station, 19880-0356, Wilmington, DE, USA 2. Institute for Materials Research, Tohoku University, Katsura 2-1-1, 980, Sendai, Japan 3. Division of Geological and Planetary Sciences, California Institute of Technology, 91125, Pasadena, CA, USA |
| Abstract: | The dielectric constants and dissipation factors of synthetic tephroite (Mn2SiO4), fayalite (Fe3SiO4) and a forsteritic olivine (Mg1.80Fe0.22SiO4) were measured at 1 MHz using a two-terminal method and empirically determined edge corrections. The results are: tephroite, κ′a= 8.79 tan δa = 0.0006 κ′b = 10.20 tan δb = 0.0006 κ′c= 8.94 tan δc= 0.0008 fayalite, gk′a = 8.80 tan δa = 0.0004 gk′b= 8.92 tan δb = 0.0018 gk′c = 8.58 tan δc = 0.0010 olivine, gk′a = 7.16 tan δa = 0.0006 gk′b = 7.61 tan δb = 0.0008 gk′c = 7.03 tan δc = 0.0006 The low dielectric constant and loss of the fayalite indicate an exceptionally low Fe3+ content. An FeO polarizability of 4.18 Å3, determined from αD(FeO) = αD (Fe2SiO4)-αD(SiO2)]/2, is probably a more reliable value for stoichiometric FeO than could be obtained from FexO where x = 0.90–0.95. 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(M2M′X2) = 2αD(MX) + αD(M′X2) is ～+2.8% for tephroite and +0.2% for olivine. The deviation from additivity in tephroite is discussed. |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ | |