It was noted that the fast ion conductor, CuBrTe, underwent structural phase transformations at 230 and 351K. The conductivities of Cu(Br,Cl)Te and Cu(Br,I)Te solid solutions were measured here in order to determine the effect of chemical substitution upon the mobility of Cu+ cations. It was found that the structural phase transitions tended to be accompanied by subtle second-order electrical phase transitions. In the case of Cu(Br,Cl)Te, the replacement of Br by smaller Cl- anions led to an increase in the room temperature conductivity and to a corresponding decrease in the activation energy; beyond that expected for a mixture of CuBrTe and CuClTe. On the other hand, the replacement of Br- by larger I- anions led to a decrease in the room-temperature conductivity and to an increase in activation energy that was proportional to that expected for a simple mixture of CuBrTe and CuITe.

R.B.Beeken, A.T.Haase, B.H.Hoerman, S.E.Sulzer: Solid State Ionics, 1996, 86-88[1], 83-7