Dependence of mechanical and electrical properties on crystal orientation of CuCr_0.95Mg_0.05O₂ ceramics

Abstract Mg-doped CuCrO2 material has emerged as a p-type semiconductor, especially, in the field of thermoelectric materials because of its lowest resistivity in delafossite material family. In this work, CuCr0.95Mg0.05O2 bulk materials were prepared in a series of sintering temperatures including 1000, 1200, and 1400°C using solid-state reaction method. From XRD results, all samples exhibit the significant existence of delafossite phase CuCrO2, and a small portion belongs to the spinel phase MgCr2O4. An interesting finding in this study is that the Vickers hardness is mainly governed by the crystallite size of (110) plane. Besides, the change in the crystallite size of (110) plane also indirectly affects the carrier concentration of the compounds with increasing sintering temperature. The highest power factor (PF) was reached for the sample prepared at the sintering temperature 1400°C with the value of 193 μW/mK2 along with the Seebeck coefficient value of 600 μV/K measured at 400°C.