Crystal-field excitations and spin-phonon interactions in DyNi2B2C: Raman scattering study

TitleCrystal-field excitations and spin-phonon interactions in DyNi2B2C: Raman scattering study
Publication TypeJournal Article
Year of Publication2010
AuthorsRho H, Klein MV, Canfield PC
Journal TitlePhysical Review B
Date Published8/27
ISBN Number1098-0121
Accession NumberISI:000281294800003
KeywordsHONI2B2C, magnetic-properties, modes, pr2cuo4, spectroscopy, superconductivity, temperature-dependence, yni2b2c

We report polarized Raman results of magnetic superconductor DyNi2B2C (T-c = 6.2 K, T-N = 10.3 K) to explore crystal-field (CF) excitations and spin-phonon interactions. In addition to the Ni-B-1g phonon mode at 199 cm(-1), we observed additional Raman modes at 124, 151, and 221 cm(-1). By careful analysis of the temperature evolution of these modes, we attribute the 124 cm-1 excitation to a CF transition. The 151 and 221 cm(-1) modes correspond to zone-folded phonons because they are completely quenched for T > T-N. With increasing temperature across T-N, the 124 cm(-1) excitation diminishes rapidly in intensity and, interestingly, an additional mode appears at 119 cm(-1). This excitation grows in intensity with increasing temperature toward 50 K and gradually decreases with increasing temperature further. We attribute the 119 cm(-1) excitation to an excited CF transition from a low-lying CF level at 5 cm(-1) to the higher CF level at 124 cm(-1). Anomalous temperature-dependent behavior of the Ni-B-1g phonon mode was observed in peak energy and in spectral width, i.e., both the phonon energy and the linewidth are enhanced in the vicinity of T-N, suggesting the presence of strong spin-phonon interactions near the antiferromagnetic ordering temperature in DyNi2B2C.

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