Anomalous Variation of the Electrical Conductivity of Quartz with Temperature at the Transformation Point

Abstract

FOR many years the variation of electrical conductivity of crystalline dielectrics with temperature has been studied by different physicists; for example, A. Joffé¹ has studied this problem with quartz, calcite, ammonium-alum, and copper sulphate, and found that their conductivity σ is expressed by log σ = A/T + B where T is the absolute temperature, A, B the material constants. More recently, W. Seith² has also studied this problem with lead chloride and iodide crystals and deduced the expressions σ = Ae^-Q/RP for the chloride, and σ = A₁e^-Q₁/RP + A₂e^-Q₂/RP for the iodide, where A, A₁ A₂ and Q, Q₁, Q₂ are material constants, T the absolute temperature, and R the gas constant. But no one has noticed that there exists any anomalous change of the electrical conductivity of quartz at the temperature 573° C.