Diffusive barrier in silver phosphate and silver borophosphate glasses

Abstract

Dielectric measurements are carried out on [60 Ag2O–x B2O3–(40 – x) P2O5] glasses in the frequency and temperature range 10−3 to 105 Hz and 120 to 400 K, respectively. The observed dielectric data show an interfacial barrier at the metal–glass contact and reveal a barrier relaxation time τ ≈ 0.1 s, barrier capacitance Cs ≈ 4 × 10−6 F, barrier width ds ≈ 8.8 nm, and dc conductivity σdc ≈ 1.67 × 10−3 Ω−1 m−1 for the [60 Ag2O–8 B2O3–32 P2O5] glass at room temperature. A capacitive contribution from BPO4 and PO4 groups in the bulk along with an interfacial layer capacitance is suggested to be responsible for the large dispersion observed in C(ω). The activation energies for three different glass compositions are found to be (0.48 ± 0.02), (0.40 ± 0.02), and (0.50 ± 0.02) eV.