Sm-Co-Cu-Ti high-temperature permanent magnets

A class of promising permanent-magnet materials with an appreciable high-te mperature coercivity of 8.6 kOe at 500 degrees C is reported. The Sm-Co-Cu- Ti magnets are prepared by arc melting and require a suitable heat treatmen t. Magnetization measurements as a function of temperature and x-ray diffra ction patterns indicate that the samples are two-phase mixtures of 2:17 and 1:5 structures. Depending on heat treatment and composition, some of the m agnets exhibit a positive temperature coefficient of coercivity. The promis ing high-temperature behavior of the coercivity is ascribed to the temperat ure dependence of the domain-wall energy, which affects the curvature of th e walls and the pinning behavior. (C) 2000 American Institute of Physics. [ S0003-6951(00)02836-9].