在铀-铪氢化物中稳定α-UH₃：结构、磁性、热力学和输运性质
Stabilization of $α$-UH$_3$ in U-Hf Hydrides: Structural, Magnetic, Thermodynamic, and Transport Properties
AI总结：
通过铪掺杂稳定α-UH₃相，研究其磁性、热力学和输运性质，发现居里温度分布和电阻特性随铪含量变化。
摘要：
铪的掺杂稳定了铀氢化物中不稳定的体心立方（bcc）α-UH₃相，使能够系统地测量其磁性、热力学和输运性质。(UH₃)₁₋ₓHfₓ氢化物（x=0.10, 0.15, 0.30, 0.40）通过氢化铀-铪前驱合金获得。粉末X射线衍射显示，随着x的增加，β-UH₃相逐渐被抑制，当x=0.30时α-UH₃占主导地位，当x=0.40时β-UH₃几乎完全被抑制。磁化测量显示所有组成均表现出铁磁行为，居里温度范围在T_C≈178-185 K之间，最大值出现在x=0.15附近；然而，自发磁化强度随铪含量显著降低，从纯β-UH₃中的1.0μB/U降至(UH₃)₀.₆₀Hf₀.₄₀中的0.46μB/U。比热数据表明，在α-UH₃丰富的氢化物样品中，居里异常显著变宽，这与铁磁非均匀性导致的T_C值分布一致。比热还显示随着铪浓度增加，Sommerfeld系数单调减小，反映了费米能级处电子态密度的减少，尤其是在(UH₃)₀.₆₀Hf₀.₄₀中。 (UH₃)₀.₆₀Hf₀.₄₀的电阻率非常大，表现出2-300 K范围内的稳健负温度系数，并且仅显示出弱磁电阻，表明输运处于强无序主导的非相干 regime。
英文摘要：
Hf substitution stabilizes the metastable body-centered cubic (bcc) $α$-UH$3$ phase in uranium hydrides, enabling systematic measurements of its magnetic, thermodynamic, and transport properties. (UH$3$)${1-x}$Hf$x$ hydrides ($x = 0.10, 0.15, 0.30, 0.40$) were obtained by hydrogenation of U${1-x}$Hf$x$ precursor alloys. Powder X-ray diffraction shows a progressive suppression of $β$-UH$3$ phase with increasing $x$, with $α$-UH$3$ domination at $x = 0.30$ and $β$-UH$3$ nearly fully suppressed at $x = 0.40$. Magnetization measurements show ferromagnetic behavior for all compositions with Curie temperatures in the range $T\mathrm{C} \approx 178$--$185$ K and a maximum near $x = 0.15$; however, the spontaneous magnetization is strongly reduced with Hf content, decreasing from $1.0,μ\mathrm{B}$/U in pure $β$-UH$3$ to $0.46,μ\mathrm{B}$/U for (UH$3$)${0.60}$Hf${0.40}$. Specific-heat data show a broadened Curie anomaly in the $α$-UH$3$ rich hydride samples, consistent with a distribution of $T\mathrm{C}$ values arising from ferromagnetic inhomogeneities. Specific heat also reveals a monotonic decrease in the Sommerfeld coefficient with increasing Hf concentration, reflecting a reduction in the electronic density of states at the Fermi level, especially in (UH$3$)${0.60}$Hf${0.40}$. The resistivity of (UH$3$)${0.60}$Hf${0.40}$ is very large, exhibits a robust negative temperature coefficient over 2--300 K, and shows only weak magnetoresistance, placing transport in a strongly incoherent, disorder-dominated regime.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
