La-Substitution Effects on the Magnetic Properties of Tetragonal Ferromagnet CeRu 2 Al 2 B

Polycrystalline and single crystalline samples of La-substituted compounds of CeRu2Al2B were grown and their magnetization and electrical resistivity were measured to examine the origins of high transition temperatures and a complex magnetic structure. A ferromagnetic(FM) and an antiferromagnetic-transition temperatures decrease linearly with increasing La concentration, which implies that the high transition temperatures are not ascribable to a quadrupolar interaction but a characteristic band structure. A competition of some kinds of magnetic interactions may be responsible for the appearance of a complex magnetic structure.