Structural-transition-driven antiferromagnetic to spin-glass transition in Cd-Mg-Tb 1/1 approximants

TL;DR

This study investigates how chemical and orientational disorder in Cd-Mg-Tb 1/1 approximants induce a transition from antiferromagnetic order to a spin-glass state, revealing the role of structural disorder in magnetic phase changes.

Contribution

It demonstrates the link between structural disorder, caused by Mg substitution, and magnetic transition from antiferromagnetic to spin-glass in Cd-Mg-Tb approximants.

Findings

Magnetic susceptibility shows antiferromagnetic to spin-glass transition with increasing Mg.

Suppression of monoclinic superlattice correlates with magnetic transition.

Disorder from Mg substitution and tetrahedral orientation drives the magnetic phase change.

Abstract

The magnetic susceptibility of the 1/1 approximants to icosahedral quasicrystals in a series of Cd85-xMgxTb15 (x = 5, 10, 15, 20) alloys was investigated in detail. The occurrence of antiferromagnetic to spin-glass-like transition was noticed by increasing Mg. Transmission electron microscopy analysis evidenced a correlation between the magnetic transition and suppression of the monoclinic superlattice ordering with respect to the orientation of the Cd4 tetrahedron at T > 100 K. The possible origins of this phenomenon were discussed in detail. The occurrence of the antiferromagnetic to spin-glass -like magnetic transition is associated with the combination of chemical disorder due to a randomized substitution of Cd with Mg and the orientational disorder of the Cd4 tetrahedra.