Magnetic domain structures of precipitation-hardened SmCo 2：17-type sintered magnets： Heat treatment effect

The typical magnetic domains of Sm（CObalFe0.25Cuo.07Zr0.02）7.4 magnets quenched through various heattreatment steps have been revealed by using magnetic force microscopy （MFM）. For the specimens in which the nominal c-axis is perpendicular to the imaging plane, the domain configurations change from plate-like for the as-sintered magnet to corrugation and spike-like for the homogenized one, and then to a coarse and finally to a finer domain structure when isothermally aged at 830℃ and then annealed at 400℃. However, only plate-like domains can be detected on the surfaces with the nominal c-axis parallel to the imaging plane. The finer domain （so-called interaction domain） is a characteristic magnetic domain pattern of the SmCo 2：IT-type magnets with high coercivities. Domain walls in a zigzag shape are revealed by means of MFM in final bulk SraCo 2：17-type sintered magnets.

Magnetic domain structures of precipitation-hardened SmCo 2:17-type sintered magnets: Heat treatment effect

The typical magnetic domains of Sm(Co_balFe_0.25Cu_0.07Zr_0.02)_7.4 magnets quenchedthrough various heat-treatment steps have been revealed by usingmagnetic force microscopy (MFM). For the specimens in which thenominal c-axis is perpendicular to the imaging plane, the domainconfigurations change from plate-like for the as-sintered magnet tocorrugation and spike-like for the homogenized one, and then to acoarse and finally to a finer domain structure when isothermally agedat 830du and then annealed at 400du. However, only plate-likedomains can be detected on the surfaces with the nominal c-axisparallel to the imaging plane. The finer domain (so-calledinteraction domain) is a characteristic magnetic domain pattern ofthe Sm--Co 2:17-type magnets with high coercivities. Domain walls ina zigzag shape are revealed by means of MFM in final bulk Sm--Co2:17-type sintered magnets.