Ordered surface structure in La1-xCaxMnO3 films

The surface of La1-xCaxMnO3 (LCMO) films with x = 0.1, 0.33, 0.5, and 0.66 has been studied; a highly ordered grain pattern induced by strain is obser ved in films with x = 0.5 and 0.66. The strain is identified to result from thermal expansion mismatch between substrate and film, and thermal expansi on anomaly may exist at a high temperature induced by possible phase transi tion in LCMO with x = 0.5 and 0.66. Such phenomenon is arresting on film gr owth and understanding colossal magnetoresistance materials as well as prov iding a new way to make ordered structures far application.