Microhardness, fracture mechanism and dielectric behaviour of flux-grown GdFeO3 single crystals

Results of indentation-induced hardness testing studies on flux-grown GdFeO3 crystals, leading to an understanding of their mechanical behaviour, are presented. The Vickers hardness of these crystals for (1 1 0) and (0 0 1) planes in the load range 0.098–0.98 N is 20.85–10.98 and 35.9–13.98 GN m−2, respectively. Load-independent values of hardness are estimated for both crystallographic planes by applying Hays and Kendall’s law. The values of fracture toughness, brittleness index and yield strength have also been calculated for Palmqvist and median cracks. The dielectric measurements on these crystals are carried out with a fully automated impedance analyser. The dielectric constants, dielectric loss and conductivity at different temperatures and frequencies of the applied field are measured and their behaviour analysed. The activation energy of electrical processes is also determined at various frequencies.