  Systematic research was performed to investigate magnetic properties of the
Tsai-type Ga-Pd-RE (RE = Gd, Tb, Dy, and Ho) systems, where both 1/1 and 2/1
quasicrystal approximants (ACs) are attainable at the same compositions as
thermodynamical stable phases. Most of the samples exhibited spin-glass
(SG)-like freezing behavior at low temperatures except Ga-Pd-Tb 2/1 AC and
Ga-Pd-Ho 1/1 AC. The former showcased antiferromagnetic order at 5.78 K while
the latter did not show any anomaly down to 1.8 K. Furthermore, 2/1 ACs were
noticed to be less frustrated than their corresponding 1/1 ACs presumably due
to the disorder-free environment in the nearest neighbors of the rare earth
sites that form a network of distorted octahedron in the 2/1 ACs. The spin
dynamic in SG samples was also characterized by means of ac magnetic
susceptibility measurements. The results evidenced a weak response of the
freezing temperatures to the measurement frequency in the Heisenberg systems,
i.e., Gd-contained ACs, in contrast to the non-Heisenberg systems, i.e., Tb, Dy
and Ho-contained ACs, where significant dependency is noticed for the latter.
The spin-glass samples were further examined by fitting their freezing
temperatures to the Vogel-Fulcher law.
