Recurring effects of Cu addition on magnetic properties in Fe-based bulk metallic glasses

Fe48 − xCuxCr15Mo14C15B6Y2 (x = 2, 5, 9 and 14 at.%) bulk metallic glasses (BMGs) have been synthesized by suction cast method and the glass-forming ability (GFA), thermal and magnetic properties are examined by X-ray diffraction, differential scanning calorimeter and vibrating sample magnetometer techniques. It has been observed that with the addition of Cu up to 9 at.% there is no significant effect on the GFA, however, with further increase of Cu content, GFA sharply deteriorates. The saturation magnetization initially increases with increasing Cu content up to 5 at.% then decreases with increasing Cu content and finally again increases with increasing Cu content. The coercivity initially decreases with increasing Cu content up to 9 at.% then increases with increasing Cu content. The observed thermal and magnetic effects in different BMG alloys have been discussed and explained in terms of the kinetics of BMG synthesization and the evaluation of different ferromagnetic phase formation.