Effect of ion irradiation on dielectric and mechanical characteristics of ErFeO3 single crystals

Results of 50 MeV lithium ion irradiation on mechanical and dielectric behaviour of flux grown erbium orthoferrite crystals are reported. It is shown that indentation induced Vicker's hardness number decreases on irradiation whereas the length of crack induced on indentation increases. Other mechanical parameters including fracture toughness, brittleness index and yield strength are calculated for un-irradiated and irradiated crystals. The change in the values of dielectric constant, dielectric loss and conductivity with temperature and frequency of the applied a.c. field in the range of 1 kHz-10 MHz after irradiation is reported. The dielectric constant versus temperature shows relaxor type of behaviour, irrespective of whether the sample is exposed to ion irradiation or not.