Structural and magnetic properties of the quasicrystal approximant Au$_{65}$Ga$_{21}$Tb$_{14}$

TL;DR

This study investigates the magnetic and structural properties of the quasicrystal approximant Au$_{65}$Ga$_{21}$Tb$_{14}$, revealing ferromagnetic interactions and an antiferromagnetic order with moments aligned perpendicular to a symmetry axis.

Contribution

It provides new insights into the magnetic ordering and anisotropy in Au-Ga-Tb quasicrystal approximants, highlighting the robustness of easy-axis anisotropy despite chemical substitution.

Findings

Dominant ferromagnetic interactions indicated by susceptibility and magnetization.

Antiferromagnetic order with moments perpendicular to a symmetry axis.

Magnetic properties similar to Au$_{72}$Al$_{14}$Tb$_{14}$ despite compositional differences.

Abstract

Magnetic properties of the quasicrystal approximant Au$_{65}$Ga$_{21}$Tb$_{14}$ were investigated by the magnetization and the neutron diffraction experiments. The temperature dependences of the magnetic susceptibility and the magnetization curve indicate dominant ferromagnetic interactions, while the whirling antiferromagnetic order was found from the neutron diffraction experiments. In the antiferromagnetic phase, the magnetic moments are aligned almost perpendicular to a pseudo five-fold symmetry axis, which should correspond to the easy-axis direction of a Tb atom. The magnetic properties similar to those of Au$_{72}$Al$_{14}$Tb$_{14}$ in spite of the difference in the electron-per-atom ratio suggest the robustness of the easy-axis anisotropy against the chemical substitution of the nonmagnetic atoms.