According to Wikipedia:Originally Posted by Robert
Lots more good stuff where that came from, like this.Neodymium is used in very powerful permanent magnets - Nd2Fe14B. These magnets are more expensive, but lighter and stronger than samarium-cobalt magnets. Neodymium magnets appear in high-quality products such as microphones, professional loudspeakers, in-ear headphones and computer hard disks where low weight, reduced size or powerful magnets are required.