Relaxing Kondo-screened Kramers doublets in CeRhSi3

Article

关键词: MAGNETIC PROPERTIES;    LATTICE BEHAVIOR;    HEAVY;    PHASE;    RH;    SUPERCONDUCTIVITY;    FLUCTUATIONS;    CETSI3;    POINT;   

DOI  :  10.1103/PhysRevB.99.125144

来源: SCIE

【 摘 要 】

CeRhSi3 is a superconductor under pressure coexisting with a weakly antiferromagnetic phase characterized by a Bragg peak at (q) over right arrow (0) = (similar to 0.2, 0, 0.5) [N. Aso et al., J. Magn. Magn. Mater. 310, 602 (2007)]. The compound is also a heavy-fermion material with a large specific heat coefficient gamma = 110 mJ mol(-1) K-2 and a high Kondo temperature of T-K = 50 K, indicating CeRhSi3 is in a strongly Kondo screened state. We apply high-resolution neutron spectroscopy to investigate the magnetic fluctuations in the normal phase, at ambient pressures, and at low temperatures. We measure a commensurate dynamic response centered around the (Q) over right arrow = (0, 0, 2) position that gradually evolves to H similar to 0.2 with decreasing temperature and/or energy transfers. The response is broadened both in momentum and energy and is not reminiscent of sharp spin wave excitations found in insulating magnets where the electrons are localized. We parametrize the excitation spectrum and temperature dependence using a heuristic model utilizing the random-phase approximation to couple relaxing Ce3+ ground-state Kramers doublets with a Kondo-like dynamic response. With a Ruderman-Kittel-Kasuya-Yosida exchange interaction within the ab plane and an increasing single-site susceptibility, we can qualitatively reproduce the neutron spectroscopic results in CeRhSi3 and, namely, the trade-off between scattering at commensurate and incommensurate positions. We suggest that the antiferromagnetic phase in CeRhSi3 is driven by weakly correlated relaxing localized Kramers doublets and that CeRhSi3 at ambient pressures is on the border between a Rudderman-Kittel-Yosida antiferromagnetic state and a Kondo-screened phase where static magnetism is predominately absent.

【 授权许可】

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