Anisotropic spin fluctuations in the triangular Kondo lattice compound CePtAl$_4$Ge$_2$ probed by site-selective $^{27}$Al NMR

Fuente: arXiv
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Autori principali: Sakai, H., Shin, S., Kambe, S., Tokunaga, Y., Harima, H., Pomjakushina, E., Park, T.
Natura: Preprint
Pubblicazione: 2025
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author Sakai, H.
Shin, S.
Kambe, S.
Tokunaga, Y.
Harima, H.
Pomjakushina, E.
Park, T.
author_facet Sakai, H.
Shin, S.
Kambe, S.
Tokunaga, Y.
Harima, H.
Pomjakushina, E.
Park, T.
contents A site-selective $^{27}$Al nuclear magnetic resonance (NMR) study is carried out on the Kondo lattice compound CePtAl$_4$Ge$_2$, which crystallizes in a rhombohedral lattice with quasi-two-dimensional Ce layers forming a triangular lattice network. Two inequivalent Al sites, Al(1) and Al(2), are unambiguously assigned by comparing measured nuclear quadrupole parameters with electric field gradients obtained from electronic structure calculations. Knight shift analysis yields distinct hyperfine coupling constants, revealing that they arise predominantly from RKKY-type transferred hyperfine fields through conduction electrons. Spin-lattice relaxation measurements reveal pronounced anisotropic spin fluctuations, and comparison of the relaxation rates between the two Al sites clarifies the momentum-space structure of these fluctuations. At low magnetic fields, $(T_1T)^{-1}$ is strongly enhanced on cooling toward the Néel temperature, indicating the growth of in-plane antiferromagnetic correlations in the paramagnetic state.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03007
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Anisotropic spin fluctuations in the triangular Kondo lattice compound CePtAl$_4$Ge$_2$ probed by site-selective $^{27}$Al NMR
Sakai, H.
Shin, S.
Kambe, S.
Tokunaga, Y.
Harima, H.
Pomjakushina, E.
Park, T.
Strongly Correlated Electrons
A site-selective $^{27}$Al nuclear magnetic resonance (NMR) study is carried out on the Kondo lattice compound CePtAl$_4$Ge$_2$, which crystallizes in a rhombohedral lattice with quasi-two-dimensional Ce layers forming a triangular lattice network. Two inequivalent Al sites, Al(1) and Al(2), are unambiguously assigned by comparing measured nuclear quadrupole parameters with electric field gradients obtained from electronic structure calculations. Knight shift analysis yields distinct hyperfine coupling constants, revealing that they arise predominantly from RKKY-type transferred hyperfine fields through conduction electrons. Spin-lattice relaxation measurements reveal pronounced anisotropic spin fluctuations, and comparison of the relaxation rates between the two Al sites clarifies the momentum-space structure of these fluctuations. At low magnetic fields, $(T_1T)^{-1}$ is strongly enhanced on cooling toward the Néel temperature, indicating the growth of in-plane antiferromagnetic correlations in the paramagnetic state.
title Anisotropic spin fluctuations in the triangular Kondo lattice compound CePtAl$_4$Ge$_2$ probed by site-selective $^{27}$Al NMR
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2509.03007