Yttrium substitutional effects on geometrically frustrated system TbNiAl

The magnetic properties of the ternary rare-earth compound TbNiAl with the hexagonal ZrNiAl crystal structure have been discussed in terms of a geometrically magnetic frustration. We have carried out measurements of magnetic susceptibility and magnetization of Tb1−xYxNiAl (0≤x≤0.30≤x≤0.3) polycrystalline samples to study the dilution effect on magnetic properties of TbNiAl. A small substitution of nonmagnetic ions of Y (x≥0.1x≥0.1) for magnetic ions of Tb stabilizes the ferromagnetic state. This finding suggests that the number of frustrated bonds is strongly reduced by introduction of nonmagnetic Y sites and a dominant ferromagnetic interaction appears instead.