| Abstract Scope |
Although Nd-Fe-B is the most powerful magnet, its Curie temperature (586K) and spin re-orientation (136K) limit the suitability for applications above 400K or below150K. In this work, we evaluate the low-temperature hard-magnetic performance of Sm2Fe17N3, with typical grain size of 2-3mm. From 295–20K and 20K, the coercivity increases linearly from 12–30kOe. The correlation between coercivity and the magnetocrystalline anisotropy field can be described by a ‘Kromuller formula’ (Hci(T)= αHA(T)-NeffMs(T)) microstructure parameter(α)=0.156; effective demagnetization constant(Neff)=0.7. Combining experiments and micromagnetic simulation, we identified that the coercivity in Sm2Fe17N3 particles is controlled by nucleation of the reversal magnetic domain. Also, the maximum energy product increases from 35–41MGOe with a decreasing temperature (295–145K), and remains almost unchanged afterwards. Therefore, in addition to its suitability for applications around room temperature, Sm2Fe17N3-based magnet also has potential for low-temperature applications such as magnetic refrigeration for the liquefaction of natural gas and hydrogen. |