 One of the most important applications of samarium is in samarium – cobalt magnets , which have a nominal composition of SmCo5 or Sm2Co17 . They have high permanent magnetization , which is about 10 @,@ 000 times that of iron and is second only to that of neodymium magnets . However , samarium @-@ based magnets have higher resistance to demagnetization , as they are stable to temperatures above 700 ° C ( cf . 300 – 400 ° C for neodymium magnets ) . These magnets are found in small motors , headphones , and high @-@ end magnetic pickups for guitars and related musical instruments . For example , they are used in the motors of a solar @-@ powered electric aircraft , the Solar Challenger , and in the Samarium Cobalt Noiseless electric guitar and bass pickups . 
