Spin fluctuations in hydrogen-stabilized Laves phase UTi2H5 |
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Authors: | Volodymyr Buturlim Micha? Falkowski Mykhaylo Paukov Oleksandra Koloskova Daria Drozdenko Milan Dopita |
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Institution: | 1. Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic;2. Immanuel Kant Baltic Federal University, Kaliningrad, Russia |
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Abstract: | Uranium Laves phase UTi2 does not exist in a pure form, but can be stabilised by the presence of hydrogen, which can be absorbed in concentration exceeding 5?H atoms/f.u. Low temperature specific heat, magnetic susceptibility, and resistivity indicate that UTi2H5 is a spin fluctuator close to the verge of magnetic ordering. Its susceptibility follows at high temperatures the Curie–Weiss law with U effective moment µeff ?= 3.1?µB/U and paramagnetic Curie temperature Θp = ?200 K. The temperature dependence of specific heat exhibits a pronounced and weakly field dependent upturn in Cp/T versus T below 10 K reflecting the effect of spin fluctuations. It can be described by an additional T½ term. The Sommerfeld coefficient γ = 256?mJ/mol K2 classifies the compound as a mid-weight heavy fermion. Spin fluctuations are affecting also electrical and thermal transport and thermoelectric power, which all resemble UAl2. A lattice anomaly at ≈ 240?K, attributed to the melting of hydrogen sublattice, reflects in most of bulk properties. |
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Keywords: | Uranium compounds Laves phase transport properties heavy-fermion metals specific heat magnetization dynamics |
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