Equation of State, Electrical Properties and Phase Transition in CuO at High Pressure

The p-V relationship for CuO at room temperature and up to 4.5 GPa has been studied using the piston-cylinder type measurement device, and its equation of state, Grneisen parameter 0, bulk modulus B0 and the first order pressure derivative B0' have been given. And the resistance-pressure and capacitance-pressure relationships at room temperature and the pressures up to 22 GPa have been studied in a diamond anvil cell using resistance and capacitance measurements. Experimental results show that several anomalous changes in resistance and capacitance occur. We conjecture that the change at about 5 GPa may be caused by the change of the interior electronic structure (electronic structure transition), and the changes at other pressures may be related to the changes of structures of states in the crystal boundary. These results are valuable to understand the mechanism of superconductivity for the copper-bearing oxide superconductors.