Samarium–cobalt magnet

Some applications, such as inertial gyroscopes and travelling wave tubes (TWTs), need to have constant field over a wide temperature range.When there are no impurities, the reversal process of the bulk magnet is equivalent to lone-domain motes, where coherent rotation is the dominant mechanism.However, due to the imperfection of fabricating, impurities may be introduced in the magnets, which form nuclei.In this case, because the impurities may have lower anisotropy or misaligned easy axes, their directions of magnetization are easier to spin, which breaks the 180° domain wall configuration.Other elements like zirconium, hafnium, and such may be added in small quantities to achieve better heat treatment response.The grinding waste produced must not be allowed to completely dry as samarium–cobalt has a low ignition point.Sintering is applied at a temperature of 1100˚C–1250˚C, followed by solution treatment at 1100˚C–1200˚C and tempering is finally performed on the magnet at about 700˚C–900˚C.[citation needed] Samarium can be substituted by a portion of other rare-earth elements including praseodymium, cerium, and gadolinium; the cobalt can be substituted by a portion of other transition metals including iron, copper, and zirconium.[15] They are utilized in high-performance motors and actuators, precision sensors and gyroscopes, and satellite systems where stability and reliability are essential.