Superconductivity and magnetic order of a new phase BCT ErRh4B4

Abstract We have succeeded in preparing a new phase ErRh 4 B 4 with a body centered tetragonal structure. It is confirmed from upper critical field and magnetization measurements that the new phase ErRh 4 B 4 is an antiferromagnetic superconductor, while it is well known that a primitive tetragonal ErRh 4 B 4 is a ferromagnetic superconductor.