Quantum Griffiths singularity in the stoichiometric heavy-fermion system CeRh$_4$Al$_{15}$
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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866910359741267968 |
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| author | Tripathi, Rajesh Adroja, D. T. Muro, Y. Sharma, Shivani Biswas, P. K. Namiki, T. Kuwai, T. Hiroto, T. Strydom, A. M. Sundaresan, A. Langridge, S. |
| author_facet | Tripathi, Rajesh Adroja, D. T. Muro, Y. Sharma, Shivani Biswas, P. K. Namiki, T. Kuwai, T. Hiroto, T. Strydom, A. M. Sundaresan, A. Langridge, S. |
| contents | We present a detailed investigation of the stoichiometric CeRh$_4$Al$_{15}$ single crystal compound using the temperature dependence of the heat capacity [$C_{\text{P}}$($T$)], electrical resistivity [$ρ$($T$)], magnetic susceptibility [$χ$($T$)], and magnetization [$M$($H$)] measurements for a magnetic field ($H$) applied in the basal plane and along the $c$-axis. The low temperature power-law behavior of $C$/$T$ $\propto$ $χ$ $\propto$ $T^{-1+α}$, the isotherm magnetization, $M \sim H^α$ with the exponent $α$ = 0.45 - 0.55, and the $T$-linear resistivity $Δρ$ $\sim$ $T^ε$ with $ε\sim$ 1 are found to be consistent with the formation of quantum Griffiths singularities in the non-Fermi-liquid (NFL) regime. We further investigated the spin dynamics of a polycrystalline sample of CeRh$_4$Al$_{15}$, using zero-field (ZF) and longitudinal-field (LF) muon spin relaxation ($μ$SR) measurements. ZF-$μ$SR measurements do not reveal any sign of long-range magnetic ordering down to 70~mK. The electronic relaxation rate ($λ$) below 0.5~K increases rapidly and shows a thermal activation-like characteristic [$T$log($λ$)$\sim$ $T$] over the entire measured temperature range between 70~mK to 4~K, indicating the presence of low energy spin fluctuations in CeRh$_4$Al$_{15}$. LF-$μ$SR measurements show a time-field ($t/H^η$) scaling of the $μ$SR asymmetry indicating a quantum critical behavior of this compound. Furthermore, inelastic neutron scattering study on the polycrystalline sample reveals two crystal field excitations near 19 and 33~meV. These features collectively provide strong evidence of NFL behavior in CeRh$_4$Al$_{15}$ due to the formation of Griffiths phase close to a $T$ $\rightarrow$ 0~K quantum critical point. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2305_16110 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Quantum Griffiths singularity in the stoichiometric heavy-fermion system CeRh$_4$Al$_{15}$ Tripathi, Rajesh Adroja, D. T. Muro, Y. Sharma, Shivani Biswas, P. K. Namiki, T. Kuwai, T. Hiroto, T. Strydom, A. M. Sundaresan, A. Langridge, S. Strongly Correlated Electrons Materials Science We present a detailed investigation of the stoichiometric CeRh$_4$Al$_{15}$ single crystal compound using the temperature dependence of the heat capacity [$C_{\text{P}}$($T$)], electrical resistivity [$ρ$($T$)], magnetic susceptibility [$χ$($T$)], and magnetization [$M$($H$)] measurements for a magnetic field ($H$) applied in the basal plane and along the $c$-axis. The low temperature power-law behavior of $C$/$T$ $\propto$ $χ$ $\propto$ $T^{-1+α}$, the isotherm magnetization, $M \sim H^α$ with the exponent $α$ = 0.45 - 0.55, and the $T$-linear resistivity $Δρ$ $\sim$ $T^ε$ with $ε\sim$ 1 are found to be consistent with the formation of quantum Griffiths singularities in the non-Fermi-liquid (NFL) regime. We further investigated the spin dynamics of a polycrystalline sample of CeRh$_4$Al$_{15}$, using zero-field (ZF) and longitudinal-field (LF) muon spin relaxation ($μ$SR) measurements. ZF-$μ$SR measurements do not reveal any sign of long-range magnetic ordering down to 70~mK. The electronic relaxation rate ($λ$) below 0.5~K increases rapidly and shows a thermal activation-like characteristic [$T$log($λ$)$\sim$ $T$] over the entire measured temperature range between 70~mK to 4~K, indicating the presence of low energy spin fluctuations in CeRh$_4$Al$_{15}$. LF-$μ$SR measurements show a time-field ($t/H^η$) scaling of the $μ$SR asymmetry indicating a quantum critical behavior of this compound. Furthermore, inelastic neutron scattering study on the polycrystalline sample reveals two crystal field excitations near 19 and 33~meV. These features collectively provide strong evidence of NFL behavior in CeRh$_4$Al$_{15}$ due to the formation of Griffiths phase close to a $T$ $\rightarrow$ 0~K quantum critical point. |
| title | Quantum Griffiths singularity in the stoichiometric heavy-fermion system CeRh$_4$Al$_{15}$ |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2305.16110 |