In situ observation of relativity between domain and indentation crack propagating in barium titanate single crystal

Instant electric field-induced 90o domain switching and propagation of indentation crack in a poled BaTiO3 single crystal, as well as sustained field-induced indentation crack propagation and 90o domain switching in an unpoled BaTiO3 single crystal have been investigated in situ using optical microscopy. The results show that the critical instant field for appearing 90o domain switching is less than that for propagation of indentation crack normal to the instant field, and there is no direct relation between crack propagating and domain switching. Delayed propagation of unloaded indentation crack in atmosphere under sustained field, which is less than the critical field for instant propagation of crack, can occur and result in enlargement of the indentation-induced 90o domain switching zones