Half-Heusler compounds UPtSn and ThPtSn: and NMR studies

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• 作者：A. Grykał ; owska ; B. Nowak
• 关键词：Actinide alloys and compounds ; Magnetic measurements ; Nuclear resonances
• 刊名：Journal of Alloys and Compounds
• 出版年：2008
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：3 April 2008
• 卷：453
• 期：1-2
• 页码：7-14
• 文件大小：246 K

摘要

Intrinsic magnetic susceptibilities of ThPtSn and UPtSn have been determined from the analysis of magnetisation isotherms recorded in the temperature range 1.9–300 K, and in magnetic field strengths up to 5 T. ThPtSn is found to be diamagnetic. Susceptibility data of UPtSn exhibit a cusp-like behaviour in the vicinity of 35 K and Curie–Weiss law above 150 K. Microscopic properties of UPtSn have been studied by and d05579e01e7"> NMR Knight shift, K, and the spin–lattice relaxation rate 1/T₁ in the paramagnetic state (  K). The Knight shift versus susceptibility χ(T) plots at temperatures T≥150  K yield the transferred hyperfine fields of +51.6 kOe/μ_B for nuclei, and − 13.5 kOe/μ_B for nuclei. Plots of 53d2733"> against χ(T) for T<150  K exhibit a deviation from the linear behaviour indicative of crystalline field effects. The temperature dependence of the 1/T₁ data of nuclei is consistent with a model of electronic structure possessing an energy gap Δ=12.3  meV and can explain the reported activated resistivity. Paramagnetic impurities act as relaxation centers in ThPtSn. Rapid spin diffusion plays an important role in relaxation while nuclear spins relax directly through dipole–dipole interactions with electron spins on magnetic impurities.