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arXiv · 1611.10126

Novel Kondo-like behavior near magnetic instability in SmB$_6$ : temperature and pressure dependences of Sm valence

N. Emi·N. Kawamura·M. Mizumaki·T. Koyama·N. Ishimatsu·G. Pristáš·T. Kagayama·K. Shimizu·Y. Osanai·F. Iga·T. Mito
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Abstract

We report a systematic study of Sm valence in the prototypical intermediate valence compound SmB$_6$. Sm mean valence, $v_{\rm Sm}$, was measured by X-ray absorption spectroscopy as functions of pressure ($1<P<13$ GPa) and temperature ($3<T<300$ K). Pressure induced magnetic order (MO) was detected above $P_c = 10$ GPa by resistivity measurements. A shift toward localized $4f$ state with increasing $P$ and/or $T$ is evident from an increase in $v_{\rm Sm}$. However $v_{\rm Sm}$ at $P_c$ is anomalously far below 3, which differs from the general case of nonmagnetic-magnetic transition in Yb and Ce compounds. From the $T$ dependence of $v_{\rm Sm}(P,T)$, we found that $v_{\rm Sm}(P,T)$ consists of two different characteristic components: one is associated with low-energy electronic correlations involving Kondo like behavior, and the other with high-energy valence fluctuations.

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N. Emi, N. Kawamura, M. Mizumaki, T. Koyama, N. Ishimatsu, G. Pristáš, T. Kagayama, K. Shimizu, Y. Osanai, F. Iga, T. Mito. 2018-03-28. Novel Kondo-like behavior near magnetic instability in SmB$_6$ : temperature and pressure dependences of Sm valence. https://doi.org/10.1103/physrevb.97.161116

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