7.1 Introduction

Samarium-Cobalt type permanent magnets were discovered in the 1960's by Strnat and coworkers [1]. The high magnetic moment of Sm and Co as well as the high magnetocrystalline anisotropy are the reason for the excellent magnetic properties of this material. As compared to NdFeB type magnets SmCo magnets have superior properties at elevated temperatures due to their high Curie temperatures ( $720 ^\circ\mathrm{C}$ for SmCo$_5$ and $820 ^\circ\mathrm{C}$ for Sm$_2$Co$_{17}$ [80]) and low temperature coefficients of coercivity, which makes it the best material currently available for high temperature magnets.

Thus, the HITEMAG project of the European Union [2], whose objective is the development and optimization of magnetic materials for high temperature applications, concentrates on this material.