Laser-induced transverse voltage effect in c-axis inclined CuCr0.98Mg0.02O2 thin films with dominant phonon thermal conductivity

Abstract

CuCr1−xMgxO2 (x = 0 and 0.02) epitaxial thin films were prepared on 5°/10° vicinal cut α-Al2O3 (000l) substrates using pulsed laser deposition. The laser-induced thermoelectric voltage (LITV) effect in these inclined delafossite thin films was observed for the first time. The thin films were characterized by resistivity temperature measurement and atomic force microscopy. Because of the enhanced resistivity anisotropy and high carrier concentration in the ab-plane owing to Mg doping, the 10°-tilted CuCr0.98Mg0.02O2 film exhibits an evident LITV signal with a maximum transverse thermoelectric voltage of 156 mV. Thermal conductivity results indicate that CuCr1−xMgxO2 (x = 0 and 0.02) films have a dominant phonon thermal conductivity, which may contribute to a long decay time for the LITV signal. These results indicate potential for future transverse thermoelectric applications based on transparent conductive oxides.