High-Temperature Magnetic Properties of Exchange-Coupled Sm-Co/Nd-Fe-B Hybrid Nanocomposite Magnets

We report high-temperature magnetic properties of hybrid nanocomposite magnets composed of Sm2 Co17 and Nd2Fe14B hard magnetic phases prepared via high-energy ball milling and warm compaction. The magnetic and structural properties of the Sm2Co17/Nd2Fe 14B nanocomposite magnets were investigated for different phase fractions of the two hard phases. The effective interphase exchange coupling resulting from the small grain size (∼14 nm) of the hard phases leads to a single-phase-like demagnetization behavior with improved energy product ${(BH)}_{{{\max}}}$ . The Sm2Co17/Nd2Fe14B isotropic nanocomposite magnets exhibit a ${(BH)}_{{{\max}}}$ value up to 15.5 MG·Oe at room temperature. High-temperature magnetic characterizations show that the Sm2Co17/Nd2Fe14B hybrid nanocomposite magnets have remarkably better thermal stability than single-phase Nd2Fe14B magnets and also have enhanced ${(BH)}_{{{\max}}}$ compared to single-phase Sm 2Co17 magnets.