YbNi$_4$Mg: Superheavy fermion with enhanced Wilson ratio and magnetocaloric effect
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arXiv
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| Auteurs principaux: | , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866912151977852928 |
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| author | Zhang, Xiaoci Zhang, Te Zhuang, Zhaotong Leng, Zixuan Wei, Zixuan Liu, Xinyang Xiang, Junsen Zhang, Shuai Sun, Peijie |
| author_facet | Zhang, Xiaoci Zhang, Te Zhuang, Zhaotong Leng, Zixuan Wei, Zixuan Liu, Xinyang Xiang, Junsen Zhang, Shuai Sun, Peijie |
| contents | A comprehensive study of the low-temperature properties of YbNi$_4$Mg has revealed evidence of a superheavy-fermion state, characterized by a large electronic specific-heat coefficient $γ_0$ $\approx$ 5.65 J mol$^{-1}$ K$^{-2}$ and an elevated Wilson ratio $R_W$ = 32.1. No magnetic ordering was observed down to 70 mK; however, a broad maximum appears in the specific heat at $T^*$ = 0.3 K, along with a shoulder in the derivative of susceptibility d$χ$/d$T$ and resistivity d$ρ$/d$T$. These features indicate a cooperative yet short-ranged magnetism entwined with the superheavy Fermi liquid. The large Wilson ratio, which is also detected in other superheavy-fermion compounds lacking long-range order, might be a signature of residual spin fluctuations. Applying a weak magnetic field of $\sim$0.1 T induces a metamagnetic-like crossover, as demonstrated by the quasi-adiabatic demagnetization measurements showing a broad minimum in the temperature-field trace. Here, an enhanced magnetocaloric cooling effect stemming from the field-sensitive superheavy-fermion state is observed, rivaling that of the well-established insulating magnetic coolants like the rare-earth garnet Gd$_3$Ga$_5$O$_{12}$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_08043 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | YbNi$_4$Mg: Superheavy fermion with enhanced Wilson ratio and magnetocaloric effect Zhang, Xiaoci Zhang, Te Zhuang, Zhaotong Leng, Zixuan Wei, Zixuan Liu, Xinyang Xiang, Junsen Zhang, Shuai Sun, Peijie Strongly Correlated Electrons A comprehensive study of the low-temperature properties of YbNi$_4$Mg has revealed evidence of a superheavy-fermion state, characterized by a large electronic specific-heat coefficient $γ_0$ $\approx$ 5.65 J mol$^{-1}$ K$^{-2}$ and an elevated Wilson ratio $R_W$ = 32.1. No magnetic ordering was observed down to 70 mK; however, a broad maximum appears in the specific heat at $T^*$ = 0.3 K, along with a shoulder in the derivative of susceptibility d$χ$/d$T$ and resistivity d$ρ$/d$T$. These features indicate a cooperative yet short-ranged magnetism entwined with the superheavy Fermi liquid. The large Wilson ratio, which is also detected in other superheavy-fermion compounds lacking long-range order, might be a signature of residual spin fluctuations. Applying a weak magnetic field of $\sim$0.1 T induces a metamagnetic-like crossover, as demonstrated by the quasi-adiabatic demagnetization measurements showing a broad minimum in the temperature-field trace. Here, an enhanced magnetocaloric cooling effect stemming from the field-sensitive superheavy-fermion state is observed, rivaling that of the well-established insulating magnetic coolants like the rare-earth garnet Gd$_3$Ga$_5$O$_{12}$. |
| title | YbNi$_4$Mg: Superheavy fermion with enhanced Wilson ratio and magnetocaloric effect |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2412.08043 |