Abstract
The research of the Nd-Fe-B magnet was started from an expectation that B and/or C might expand Fe-Fe interatomic distances in rare-earth iron alloys, leading to increase the Curie temperature of them. After the success in developing the powerful Nd-Fe-B sintered magnets with record high energy products, however, a crystal structure analysis revealed that Fe-Fe pairs having small interatomic distances existed also in the Nd-Fe-B alloy. It is emphasized that the success in this work is a result of many fortunate matters which were not expected in the beginning.
