Microstructure and Magnetic Properties of Textured Melt-Spun CoMnFeNi High-Entropy Alloy

High-entropy alloys (HEAs) containing 3d transition metals provide a versatile platform for tuning magnetic properties due to their chemically complex local environments and competing exchange interactions. In this work, CoMnFeNi HEA ribbons were synthesized by melt spinning (MS) directly from elemental powders, combining alloy formation and rapid solidification in a single step. The effect of wheel speed (10–40 m/s) on the structure, chemical homogeneity and magnetic behavior was systematically investigated. All ribbons crystallize in a single-phase FCC structure, while variations in the relative intensities of the (111) and (200) reflections indicate the development of the solidification-induced crystallographic texture. The MS10 ribbon remains chemically homogeneous, whereas MS40 exhibits nanoscale Mn-Fe segregation. These processing-induced differences lead to magnetic behavior ranging from weak paramagnetism in the MS10 to pronounced ferromagnetism in the MS20, MS30, and MS40 ribbons. Exchange-bias effects observed at 5 K further indicate ferromagnetic-antiferromagnetic exchange coupling associated with nanoscale chemical heterogeneity. Overall, the results demonstrate that wheel speed during melt spinning provides an effective route to tune the magnetic properties of CoMnFeNi ribbons through its influence on crystallographic texture, microstructure, and chemical homogeneity.