Formation and magnetic properties of Ga-Pd-Tb 2/1 approximant

The formation and magnetic properties of Tsai-type approximants in the Ga-Pd-Tb system were investigated. The 2/1 approximant with a lattice parameter of 2.313 nm formed in the Ga50.2Pd35.3Tb14.5 alloy annealed at 973 K for 100 h. The 2/1 approximant transformed into the corresponding 1/1 approximant through annealing at 1073 K in the alloy. For the 2/1 approximant, magnetic susceptibility measurements showed a sharp cusp at T-N similar to 5.8 K, and both the field-cooled and zero-field-cooled susceptibilities coincided, indicating an antiferromagnetic transition at T-N. This is the first instance of long-range magnetic order in 2/1 approximants. On the other hand, spin-glass-like behavior was observed in the susceptibility for the 1/1 approximant, which may be attributed to the relatively large frustration of the icosahedral clusters in the 1/1 approximant.