CeB6 macroscopically revisited

TL;DR

This study investigates the symmetry properties of CeB6's ordered states using magnetic susceptibility and magnetostriction, challenging the conventional antiferroquadrupolar model and suggesting the need for an alternative explanation.

Contribution

The paper provides experimental evidence that questions the antiferroquadrupolar model of CeB6 phase II, proposing a new approach based on a unidimensional cube representation.

Findings

Antiferromagnetic state confirmed as tetragonal.

No deviation from cubic symmetry in the antiferroquadrupolar phase.

Inconsistency of the antiferroquadrupolar model with observed wave-vector.

Abstract

Magnetic susceptibility anisotropy and high sensitivity magnetostriction measurements are used to investigate the symmetry of CeB6 ordered states. The antiferromagnetic state is confirmed as tetragonal, but no deviation from the cubic symmetry is observed in the so-called antiferroquadrupolar phase, where only volume effects are detected. In this phase, the temperature dependence of the strain field-susceptibilities is typical of non-ordered quadrupoles. Moreover, while an antiferroquadruplar order should be cubic, this symmetry is incompatible with the <1/2 1/2 1/2> ordering wave-vector. The antiferroquadrupolar description of CeB6 phase II is clearly inconsistent and an alternative model, based on a unidimensional representation of the cube, has to be sought for.