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 Sm
₂
Co
₁₇
and Nd
₂
Fe
₁₄
B hard magnetic phases prepared via high-energy ball milling and warm compaction. The magnetic and structural properties of the Sm
₂
Co
₁₇
/Nd
₂
Fe
₁₄
B 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 Sm
₂
Co
₁₇
/Nd
₂
Fe
₁₄
B isotropic nanocomposite magnets exhibit a (BH)
_max
value up to 15.5 MG·Oe at room temperature. High-temperature magnetic characterizations show that the Sm
₂
Co
₁₇
/Nd
₂
Fe
₁₄
B hybrid nanocomposite magnets have remarkably better thermal stability than single-phase Nd
₂
Fe
₁₄
B magnets and also have enhanced (BH)max compared to single-phase Sm
₂
Co
₁₇
magnets.