Spontaneous partitioning of the Ni + C_(60) thin film grown at RT

摘要

We report on the pattern formation in the thin film of the Ni+C_(60) mixture deposited on the MgO(001) substrate at room temperature (RT). Using magnetic force microscopy a periodic array of the magnetic domains has been revealed. The domains reflect hidden partitioning of the Ni + C_(60) film (i.e., separated Ni- and C_(60)-rich zones) that has not been observed by other applied methods. The effect indicates that even at RT, spontaneous separation of the Ni and C_(60) phases may set in during the growth of the hybrid film. Thermal annealing (for 1 h at 500 ℃) leads to dramatic rearrangement of the Ni + C_(60) structure which (consequently) also results in the loss of the magnetic domain system. This phenomenon points out the thermodynamic instability of the as-prepared hybrid film that can (at elevated temperatures) trigger the process of the Ni and C_(60) phase separation.