Atomic structure and thermal behavior of (Co0.65,Fe0.35)72Ta8B20 metallic glass with excellent soft magnetic properties

• New soft magnetic metallic glass with a high thermal stability was produced.
• The atomic structure was studied by high-energy synchrotron X-ray diffraction.
• The new alloy showed a wide supercooled liquid region of 51 K.
• A very low coercivity of 0.4 A/m was measured for the relaxed alloy.
• Soft magnetic behavior was significantly improved after annealing.

New soft magnetic (Co0.65,Fe0.35)72Ta8B20 metallic glass has been synthesized and its atomic structure and thermal stability have been studied using high-energy synchrotron X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. Analysis of the pair correlation functions (PDF) indicates a notable shift in position of the first PDF peak to a lower distance and the decreasing the average coordination number of the first shell, compared to the (Co0.65,Fe0.35)62Ta8B30 glassy alloy, recently produced. DSC analysis shows that the new alloy has a wide supercooled liquid region of 51 K and relatively high activation energy of crystallization of about 445 kJ/mol, calculated according to the Kissinger and Ozawa methods, which demonstrates its high thermal stability. Magnetic measurements show that the new alloy exhibits outstanding soft magnetic properties, i.e., very low coercivity of 1.2 A/m, high saturation magnetization of 93.5 Am2/kg and Curie temperature of 660 K, which are significantly larger than those of (Co0.65,Fe0.35)62Ta8B30 glassy ribbon. The influence of the annealing treatment on evolution of the soft magnetic properties of the (Co0.65,Fe0.35)72Ta8B20 glassy ribbons has been investigated.