2009/03/30 by Hiroaki Inoue, H. Inoue, S. Tani +21 · 18 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Atomic physics #Chemistry #Condensed matter physics #Crystallography #Excited state #Magnetic field #Magnetization #NMR spectra database #Nuclear magnetic resonance #Organic and Molecular Conductors Research #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Singlet state #Spectral line #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.79.174418
published in Physical Review B 79(17) (American Physical Society) · 19 pages, 9 figures, submitted to PRB (in press)
arxiv created 2009/03/30 · openalex publication_date 2009/05/12 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
63/65Cu- and 35/37Cl-NMR experiments were performed to investigate triplet localization in the S=1/2 dimer compound NH4CuCl3, which shows magnetization plateaus at one-quarter and three-quarters of the saturation magnetization. In 63/65Cu-NMR experiments, signal from only the singlet Cu site was observed, because that from the triplet Cu site was invisible due to the strong spin fluctuation of onsite 3d spins. We found that the temperature dependence of the shift of 63/65Cu-NMR spectra at the singlet Cu site deviated from that of macroscopic magnetization below T=6 K. This deviation is interpreted as the triplet localization in this system. From the 35/37Cl-NMR experiments at the 1/4-plateau phase, we found the two different temperature dependences of Cl shift, namely, the temperature dependence of one deviates below T=6 K from that of the macroscopic magnetization as observed in the 63/65Cu-NMR experiments, whereas the other corresponds well with that of the macroscopic magnetization in the entire experimental temperature region. We interpreted these dependences as reflecting the transferred hyperfine field at the Cl site located at a singlet site and at a triplet site, respectively. This result also indicates that the triplets are localized at low temperatures. 63/65Cu-NMR experiments performed at high magnetic fields between the one-quarter and three-quarters magnetization plateaus have revealed that the two differently oriented dimers in the unit cell are equally occupied by triplets, the fact of which limits the theoretical model on the periodic structure of the localized triplets.