Departing from the conventional method of coupling soft and hard magnetic phases to improve remanence, a novel paradigm is proposed, in which exchange coupling is engineered between an amorphous (Am) soft magnetic phase and a nanocrystalline (NG) hard magnetic phase. By tailoring the amorphous-to-nanocrystalline ratio, the remanence and maximum energy product $\left[{\left(BH\right)}_{\max }\right]$ were concurrently adjusted. Micromagnetic simulations reveal that the ${\mathrm{SmCo}}_5$ amorphous-nanocrystalline structure effectively facilitates the pinning of the amorphous phase by the hard magnetic nanocrystals during the demagnetization process, leading to a remarkable remanence enhancement. The simulated remanence ratio $(M_{\mathrm{r}}/M_{\mathrm{s}})$ increased by over 70%, from 0.52 to 0.89. Experimentally, SmCo bulk magnets with varying amorphous content were fabricated and characterized. The results show that the amorphous-nanocrystalline magnets exhibit an enhanced remanence ratio and improved $({BH)}_{\max }$ compared to the fully nanocrystalline samples. The underlying mechanism was investigated through a combination of theoretical and experimental techniques, including micromagnetic simulations of the magnetization reversal process, first-order reversal curve (FORC) analysis, and in situ Lorentz microscopy for domain observation. All results consistently indicate that the significant remanence enhancement originates from strong interphase exchange coupling between the amorphous and nanocrystalline phases. This approach offers a potential pathway for optimizing the performance of rare-earth permanent magnets.

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• Magnetic coupling
• Amorphous materials
• Nanocrystals
• Permanent magnets
• Lorentz microscopy
• Magnetization measurements
• Micromagnetic modeling