Evidence for magnetic-field-induced quadrupolar ordering in the heavy-fermion superconductor PrOs4Sb12

• Published in: Journal of the Physical Society of Japan Vol. 72; no. 5; pp. 1002 - 1005
• Main Authors: KOHGI, Masahumi, IWASA, Kazuaki, SUGAWARA, Hitoshi, NAKAJIMA, Motoki, METOKI, Naoto, ARAKI, Shingo, BERNHUEFT, Nick, MIGNOT, Jean-Michel, GUKASOV, Arsen, SATO, Hideyuki, AOKI, Yuji
• Format: Journal Article
• Language: English
• Published: Tokyo Institute of Pure and Applied Physics 01-05-2003; Physical Society of Japan; The Physical Society of Japan
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties; Physics; Properties of type I and type II superconductors; Superconductivity; Antiferromagnetism; Level crossing; superconductivity; Ground states; Osmium alloys; Neutron diffraction; Antimony alloys; Ternary alloys; Magnetic field effects; PrOs4Sb12; Singlet state; heavy fermion; Crystal field; Excited states; Experimental study; quadrupolar ordering; Praseodymium alloys; Heavy fermion superconductors; Rare earth alloys; Quadrupole moments; Antiferroquadripolar order
• ISSN: 0031-9015; 1347-4073
• DOI: 10.1143/jpsj.72.1002

Neutron diffraction experiments on the heavy-fermion superconductor PrOs4Sb12 revealed that a small antiferromagnetic moment, parallel to [010] (y-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 PrOs4Sb12 is the Γ1 singlet and the quadrupolar ordering is induced due to level crossing with an excited state under a magnetic field.