Formation and magnetic properties of metastable phases observed in the Fe50(HfxTa1−x)50 films by ion beam mixing

Metastable phase formation and magnetic properties of the Fe50(HfxTa1−x)50 (x = 0, 0.2, …, and 1) thin films induced by ion beam mixing are studied. The results show that unique amorphous phases could be formed in all the six multilayered films. Interestingly, preferred orientations and formation of BCC-Hf phase were observed in the Fe50Hf50 multilayered films at as-deposited state and after irradiated to doses less than 6 × 1014 Xe+/cm2. In addition, good soft magnetic properties were obtained in the formed amorphous phases. The Fe50Hf40Ta10 amorphous phase owns the maximum magnetization of 45 emu/g (i.e., 1.21 μB per Fe atom) at 5 K, with a saturate magnetization of 7.5 emu/g and a small coercivity Hc = 7 Oe at room temperature. The possible mechanisms responsible for the observations are discussed in terms of atomic collision theory and crystallography.