Influence of Oxygen or Carbon Impurities on Domain Structure of Sm-Co Magnets

Abstract

Magnetic domain structure changes during a demagnetization process of 2-17 type Sm-Co magnets with different amounts of carbon and oxygen were observed using a Kerr effect microscope. Moreover, the effects of the excess carbon and excess oxygen compositions on the demagnetization process of the magnets were investigated. As a result, it is found that in the Sm-Co magnets with high carbon and oxygen composition, the nucleation of reversal magnetic domains inside grains during the demagnetization process easily occurs at a lower demagnetization field strength. The nucleation of the reversal magnetic domain in grains causes a decrease in a squareness ratio of a demagnetization curve.