MAGNETIC-ORDERING IN TERBIUM ALLOYS

The magnetic-ordering temperatures of alloys of Tb with the nonmagnetic diluents Sc, Y, La, Lu, Yb, Mg, and Th were investigated. The initial ordering temperature for transition into the helical structure is discussed in terms of the magnitude of the indirect-exchange-interaction strength. The second ordering temperature for transition into the ferromagnetic state was also determined. In the La, Yb, and Th alloys the helical structure is suppressed with increasing concentration of nonmagnetic diluents and the ferromagnetic transition is then associated with the initial ordered state. For the Sc, Y, Lu, and Mg alloys it is the ferromagnetic state which is suppressed relative to the helical state. The ordering temperatures drop particularly rapidly for the Mg alloys with the disappearance of the ferromagnetic transition occurring at only 7 at.%. © 1979 The American Physical Society.