Mechanical properties of Cu₆PS₅І superionic crystals and thin films

Abstract

The hardness and Young’s modulus dependences on the instrumented indentation depth profiles in Cu₆PS₅І single crystals and Cu₆PS₅І-based thin films were investigated. The measurements of mechanical parameters were performed at room temperature by instrumented indentation in the continuous stiffness measurement mode with harmonic modulation of load during its linear increase. The variations of the hardness and Young’s modulus in Cu₆PS₅І single crystals were interpreted in the framework of the deformation gradient model. The decrease of micro-hardness in Cu₆PS₅І-based thin film observed with copper content increase was explained by the formation of conductive clusters and dendrites.