Electrical Conduction of La₂Cu_1-xZn_xO_4+δ at High Temperature

Abstract

Electrical conductivity and Seebeck coefficient of La₂ Cu_1-xZn_xO_4+δ were measured as a function of temperature and oxygen partial pressure. In the temperature region from 500° to 800°C, the electrical conductivity decreased as temperature increased. This is due to decrease in excess interstitial oxygen and hole as temperature increased. Below 500°C, the semiconductive behavior was observed for the specimens containing more than 0.03 Zn. The XPS peak near the Fermi level vanished on Zn substitution. Seebeck coefficient increased as temperature increased. This is also due to the oxygen nonstoichiometry, and corresponds to the change in the electrical conductivity. Thermoelectrical efficiency of La₂Cu_1-xZn_xO_4+δ was slightly lower than that of La₂CuO₄.