Microstructure and magnetic properties of exchange-coupled nanocomposite Sm0.75Zr0.25(Fe0.8Co0.2)11Ti alloy

摘要

The preparation of ThMn12-type Sm-based permanent alloy with excellent magnetic properties has always been the focus of research. In this work, Sm0.75Zr0.25(Fe0.8Co0.2)11Ti alloys were prepared by arc melting followed by melt spinning, and then heat treatment at 800 degrees C for 5-30 min was conducted to optimize magnetic properties. Well exchange-coupled Sm0.75Zr0.25(Fe0.8Co0.2)11Ti alloy containing 1:12 phase and alpha-Fe phase was obtained successfully. With the increase of annealing time, the grain size is greatly increased from-30 nm of 5 min to-60 nm of 30 min, which is the main reason for the appearance of "kink" in the second quadrant demagneti-zation curve, and this can be confirmed by micromagnetic simulation. Moreover, the results from micromagnetic computation show that the magnetization vector of alpha-Fe phase has reversed at zero field in the coarse-grained model, but this reversal is not observed in the fine-grained model. The inconsistent reversal of hard and soft magnetic phases leads to the appearance of the "kink".

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