Microstructure and nano-scratch behaviors of La0.7Sr0.3MnO3 films

The La0.7Sr0.3MnO3 (LSMO) films were prepared at various substrate temperatures on si(100) by DC magnetron sputtering method. The microstructure and nano-scratch behaviors of the films were investigated. The results indicate that the films are single phase with perovskite distorted cubic structure and the texture orientation changes obviously with the increase of substrate temperature. A smooth and dense nanocrystalline LSMO film is obtained at high substrate temperature. The (110) preferred orientation growth is beneficial to the improvement of nano-scratch resistance of the films. The friction coefficient between the films and the diamond tip depends on the critical load (Lc). Elastic deformation is the dominant deformation mechanism and the friction coefficient is about 0.08–0.14 for all the films when the loading normal load is less than Lc. When the loading load is larger than Lc, the delamination or detachment of the films occur and the friction coefficient increases abruptly near the Lc. The films deposited at 480 °C and 680 °C possess higher Lc which is about 77 mN due to lower hardness. The suitable decrease in hardness can enhance cohesion strength and scratch resistance of the films.