Electrical conductivity and pyroelectricity of lithium–potassium sulphate single crystal in the temperature range 300–950 K

The DC electrical conductivity ( σ) along the a- and c-axes and the pyroelectric coefficient ( p) along the pyroelectric c-axis of lithium–potassium sulphate (LKS) single crystal are measured in the temperature range 300–950 K. The measurements of σ show anomalous behaviour at the transition point around 705 K. The σ– T relationship reveals an activation energy of conduction along the c-axis of 0.85 eV above and 0.37 eV below the transition temperature, respectively. The effect of thermal recycling on the electric conduction is discussed. A maximum signal at about 720 K and a variation in the sign of p at about 704 K have been observed. The phase transition reported in the literature at 333 K was not confirmed by our measurements. The current density ( J) is measured as a function of the applied electric field ( E) below and above the phase transition temperature along the c- and a-axes in order to estimate the type of conduction dominated and the effect of E upon the conductivity measurements of this crystal.