Fig. 1: Conductivity of LTC with different processing conditions.

a, b Nyquist plots of the as-milled (a) and 300 °C-annealed LTC materials (b) at 25 °C. c The transient current behavior under an applied 1.0 V DC bias on the as-milled and 300 °C-annealed LTC pellets with stainless-steel electrodes. d Arrhenius plots of the as-milled and 300 °C-annealed LTC materials.