Neutron diffraction experiments on the heavy-fermion superconductor PrOs4Sb12 revealed that a small antiferromagnetic moment, parallel to  (γ-direction), is induced in the field-induced phase (H ∥ z). The analysis, based on the Γ1 singlet ground state crystal field model, shows that antiferro-order of Oyz-type quadrupole moments of Pr ions is formed in the field-induced phase. This strongly suggests that the crystal field ground-state of Pr ions in PrOs 4Sb12 is the Γ1 singlet and the quadrupolar ordering is induced due to level crossing with an excited state under a magnetic field.
- Heavy fermion
- Neutron diffraction
- Quadrupolar ordering
ASJC Scopus subject areas
- General Physics and Astronomy