CeB6 macroscopically revisited

Mehdi Amara (1) , Rose-Marie Galéra (1)

1 NEEL - MagSup - Magnétisme et Supraconductivité

Magnetic susceptibility anisotropy and high sensitivity magnetostriction measurements are used to investigate the symmetry of CeB$_6$ 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 $\langle\frac{1}{2}\frac{1}{2}\frac{1}{2} \rangle$ ordering wave-vector. The antiferroquadrupolar description of CeB$_6$ phase II is clearly inconsistent and an alternative model, based on a unidimensional representation of the cube, has to be sought.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Mehdi Amara, Rose-Marie Galéra. CeB6 macroscopically revisited. Physical Review Letters, 2012, 108, pp.026402-1. ⟨10.1103/PhysRevLett.108.026402⟩. ⟨hal-00667338⟩