Effect of anisotropic strain on the charge ordering transition in manganite films

The substrate induced anisotropic strain was found to have a significant effect on the charge ordering (CO) transition and surface morphology in Bi0.4Ca0.6MnO3 films deposited on (110)- and (111)-oriented SrTiO3 substrates. Effects of film thickness t on the CO transition were further studied. The CO transition appears at TCO when t exceeds 50nm, and develops rapidly to an excellent state as t reaches 100nm. The distinctive thickness-dependent CO transition has a close relation with the anisotropic strain relaxation process.