标题： Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for $H \parallel a$ in the Early-Stage Sample of Spin-Triplet Superconductor UTe$_2$ 显示英文标题

标题： Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for $H \parallel a$ in the Early-Stage Sample of Spin-Triplet Superconductor UTe$_2$

摘要： 我们报告了在自旋三重态超导体 UTe$_2$的早期阶段样品中，对$a$轴自旋磁化率分量的重新测量，其转变温度为$T_{\rm SC}$= 1.6 K。通过沿$b$轴以及从$b$轴向$a$轴倾斜10度方向的 Knight 移位测量，我们准确确定了$a$轴分量，而无需直接测量$a$轴的 Knight 移位。 我们的结果揭示了在超导态下，当施加$a$-轴磁场$\mu_0 H_a \sim 0.1$ T时，$a$-轴自旋磁化率大约减少了3%，这表明在早期样品和超洁净样品中，自旋磁化率的减少情况相似，其中$T_{\rm SC}$ = 2.1 K。之前报道的Knight位移没有减少的现象被归因于缺少来自超导区域的信号，以及检测到了非超导区域的残留信号。 我们还发现，$a$-轴自旋磁化率的减少随着$a$-轴磁场的增加而立即被抑制，并估计在约1.5 T时由于超导自旋旋转而完全被抑制。 显示英文摘要

摘要： We report the re-measurement of the $a$-axis spin susceptibility component in an early-stage sample of the spin-triplet superconductor UTe$_2$ with the transition temperature of $T_{\rm SC}$ = 1.6 K. Using Knight-shift measurements along the $b$ axis and at a 10-degree tilt from the $b$ axis towards the $a$ axis, we accurately determined the $a$-axis component without directly measuring the $a$-axis Knight shift. Our results reveal a decrease of approximately 3\% in the $a$-axis spin susceptibility in the superconducting state under $a$-axis magnetic field $\mu_0 H_a \sim 0.1$ T, indicating that the spin susceptibility decreases similarly in both early-stage and ultraclean samples with $T_{\rm SC}$ = 2.1 K. The previously reported absence of the reduction in Knight shift is attributed to the missing of signal from the superconducting region and to the detection of residual signals from the non-superconducting region instead. We also found that the decrease in the $a$-axis spin susceptibility is immediately suppressed with increasing the $a$-axis magnetic field and is estimated to be completely suppressed at around 1.5 T due to superconducting spin rotation.