High-frequency dielectric properties of Mg-Al-Si, Ca-Al-Si and Y-Al-Si oxynitride glasses

Abstract

Recently developed coaxial line techniques [1] have been used to determine, at room temperature, the values of the real (ε′) and imaginary (ε′') parts of the dielectric constants for some Mg-Al-Si, Ca-Al-Si and Y-Al-Si oxynitride glasses over the frequency range 500 MHz to 5 GHz. The frequency dependencies of ε′ and ε′' are consistent with the universal law of dielectric response in that (ε′-ε_t8)∝ω⁽ⁿ⁻¹⁾ and ε′'∝ω⁽ⁿ⁻¹⁾ for all glass compositions; the high experimental value of the exponent (n=1.0±0.1) suggests the limiting form of lattice loss [2] situation. In this frequency range, as previously reported [3] at longer wavelengths, the addition of nitrogen increases the dielectric constant, (ε′); in both the oxide and oxynitride glasses ε′ is also influenced by the cation, being increased with cation type in the order magnesium, yttrium, calcium as at lower frequencies.