Thermal switching in silver sulphide and some of its alloys

It has been found that the current-field characteristic of silver sulphide is non-linear and that switching can occur between a high-resistance and a low-resistance state. It is shown that this behaviour is consistent with the rapid rise of electrical conductivity with temperature in the β-phase and a discontinuous increase of conductivity by orders of magnitude when the transition to the α-phase occurs at 450°K. The low thermal conductivity of Ag2S allows a strong radial temperature gradient to exist in wires and thus assists in the formation of a core of high electrical conductance. Switching effects have also been observed in alloys of Ag2S with Ag2Se and Ag2Te.