In situ formation of dual amorphous phases with nanoscale fractal morphology by ion beam mixing in the ternary Y–Nb–Co system

Dual amorphous phases with Nb-rich and Y-rich compositions, respectively, are observed in Y25Nb30Co45 and Y15Nb40Co45 multilayered films upon ion irradiation. The interfaces of the two amorphous phases are also identified by high-resolution transmission electron microscopy associated with the Fourier transformation of the image. Interestingly, the obtained dual amorphous phases feature fractal morphology with a fractal dimension of 2.54, suggesting that the growth of the amorphous phases is through a diffusion-limited aggregation model.