Magnetic properties and microstructures of multi-component Sm–Co-based films prepared by high-throughput experiments

Sm–Co-based films play an irreplaceable role in special applications due to their high curie temperature and magnetocrystalline anisotropic energy, especially in heat-assisted magnetic recording (HAMR), but the complex composition of Sm–Co phase and unclear synergistic coupling mechanisms of multi-elemental doping become the challenges to enhance the properties. In this work, a novel strategy combining magnetron sputtering and a high-throughput experiment method is applied to solve the above-mentioned problems. Fe/Cu co-doping highly increases the remanence while maintaining a coercivity larger than 26 kOe, leading to an enhancement of the magnetic energy product to 18.1 MGOe. X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) reveals that SmCo₅ phase occupies the major fraction, with Co atoms partially substituted by Fe and Cu atoms. In situ Lorentz transmission electron microscopy (LTEM) observations show that the Sm (Co, Cu)₅ phase effectively prohibits domain wall motions, leading to an increase of coercivity (H_c). Fe doping increases the low saturation magnetization (M_s) and low remanence (M_r) due to the Fe atom having a higher saturation magnetic moment. The magnetization reversal behaviors are further verified by micromagnetic simulations. Our results suggest that Sm–Co-based films prepared via Fe/Cu co-doping could be a promising candidate for high-performed HAMR in the future.

Graphical abstract