Influence of Cu-content on the hard magnetic properties of Sm(Co,Cu) 2:17 compounds

Sm(Co 1-x Cu x ) 7.8 alloys with 0.07 5 type. Annealing at about 1070 K yielded maximum coercive fields, I H c . The dependence of the coercivity maximum on the Cu-content shows no correlation with the primary magnetic properties of both matrix and precipitate phase. Domain wall energies were determined by means of the magneto-optical Kerr-effect. Coercive fields in bulk samples are obtained when the domain wall energy within the precipitate phase is lower than within the matrix, i.e. there is an attractive interaction between domain wall and precipitates.