Effect of Mn doping on magnetic properties, magnetic domain structures and microstructures of 2-17 type Sm-Co magnets

Magnetic properties, magnetic domain structures and microstructures of Sm(Fe 0.328 Cu 0.055 Zr 0.017 Mn x Co bal ) 7.65 (x=0.005, 0.010) were investigated. Even with Mn content increased, magnetic properties didn't deteriorate, remanent magnetic flux density, B r , maximum energy product, [ BH ] m and squareness, H k / H cj ( H k is a reverse magnetic field value when magnetization becomes 90 % of B r ), exceeded 12 kG, 33.5 MGOe and 70 %, respectively in both samples. However, a mechanism of magnetic reversal was different, reverse magnetic domains were easy to propagate from grain boundaries in x=0.005, grain interior in x=0.010, respectively. In microstructures, Cu concentration increased in grain boundaries, and cell size enlarged with an increase in Mn content. Because microstructures were formed properly and its size was enlarged, which produce strong pinning force, and negative effects by doping non-ferromagnetic element Mn was compensated.