Analyzing indentation stress–strain response of LaGaO3 single crystals using spherical indenters

In this work, a new approach to spherical nanoindentation analyses has been described and utilized to study the anisotropy of mechanical properties for (1 0 0) and (0 0 1) LaGaO3 single crystals. Unlike sharp indenters, indentations by spherical indenters permit the nanoindentation load–displacement curve to be converted more reliably into indentation stress–strain curves. Using a new definition of indentation strain, we present indentation stress–strain curves that are relatively insensitive to the radii of the indenters. These curves allow the modulus of the sample to be evaluated from the elastic loading segment, instead of the common practice of approximating it from the elastic unloading segment. These measurements indicate that the (1 0 0) LaGaO3 single crystal has a higher modulus and a higher hardness compared to the (0 0 1) sample.