Superionic Solids Research Articles

Electrical conduction in some important copper based superionic solids

Measurement of the thermoelectric power (S) and electrical conductivity (σ) of six superionic solids namely CuI, CuPb3Br7, Cu2HgI4, Cu3CdI5, Cu3RbCl4, Cu7(C6H12NH3)Br8 and Cu16Rb4I7Cl13 are reported from 300 K to nearly the melting point of each material. The logσT andS againstT−1 plots are linear in some temperature ranges with different slopes. For each material they show two distinct regions: one corresponding to superionic (SP) and the other to normal phase (NP). In the superionic phase, Cu+ ions are the main entity of charge carrier and an extended lattice gas model explains the transport mechanism fairly well. On the higher temperature side of SP, the other cation in the material starts contributing significantly toσ. In the normal phase the conduction is mainly due to Frenkel defects (Cu+ ions at interstitial sites). The enthalpy for migration and heat of transport of these defects has also been evaluated for CuI, CuPb3Br7, Cu2HgI4 and Cu3CdI5. The formation energy of defects has also been calculated for CuI and Cu3CdI5. Normal phase has not been obtained in Cu3RbCl4, Cu7(C6H12NCH3)Br8 and Cu16Rb4I7Cl13 as their phase transition temperatures lie below room temperature.

Study of copper ion superionic solids in the system (1 ? x)Cul:xCdl2

Electrical transport studies of five compounds (x = 0, 0,25, 0.33, 0.50 and 0.75) in the system (1 −x) Cul:xCdl2have been reported. It has been observed that all compounds of this system undergo phase transition from lower temperature low conductingβ-phase to higher temperature high conductivityα-phase. The phase transition temperature (Tp) decreases systematically withx being 642 forx = 0 and 500 K forx = 0.50. AboveTp all compounds are typical superionic solids with Cu+ ion as the entity of charge carrier. From the stability, temperature span of superionic phase,Tp andσ values point of view Cu3Cdl5 (x = 0.25) appears to be the best superionic solid of this system. The extended lattice gas model has been shown to suit better for explaining the electrical transport of solids with O⩽x ⩽ 0.5 of this system in superionic solid phase. BelowTp all compound of this sytem behave as normal ionic solid with relatively high conductivity. They yield usual “Knee temperature” and below this temperature conductivity becomes extrinsic. The activation enthalpy, heat of transport and enthalpy for the formation of defects have also been evaluated from experimental electrical conductivity and thermoelectric power data in each case.

Superionic solids: principles and applicationsby S. Chandra

<i>Superionic solids: principles and applications</i>by S. Chandra

Superionic solids: principles and applications by S. Chandra

<i>Superionic solids: principles and applications</i> by S. Chandra

Superionic Solids: Principles and Applications

Suresh Chandra 1981 Amsterdam: North-Holland xi + 404 pp price $78 This is a comprehensive and readable monograph on the new subject of superionic solids. These solids have electrical conductivity comparable to that of liquid electrolytes, which makes them particularly attractive for commercial applications.