Clear Reduction in Spin Susceptibility and Superconducting Spin Rotation for 𝐻∥ð'Ž in the Early-Stage Sample of Spin-Triplet Superconductor UTe2

• Published in: Journal of the Physical Society of Japan 2024-12, Vol.93 (12), p.1
• Main Authors: Kitagawa, Shunsaku, Nakanishi, Kousuke, Matsumura, Hiroki, Takahashi, Yuki, Ishida, Kenji, Tokunaga, Yo, Sakai, Hironori, Kambe, Shinsaku, Nakamura, Ai, Shimizu, Yusei, Homma, Yoshiya, Li, Dexin, Honda, Fuminori, Miyake, Atsushi, Aoki, Dai
• Format: Article
• Language: English
• Subjects: Magnetic fields; NMR; Nuclear magnetic resonance; Rotation; Superconductivity; Transition temperature
• ISSN: 0031-9015; 1347-4073
• DOI: 10.7566/JPSJ.93.123701

We report the re-measurement of the a-axis spin susceptibility component in an early-stage sample of the spin-triplet superconductor UTe2 with the transition temperature of TSC = 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 μ0Ha ∼ 0.1 T, indicating that the spin susceptibility decreases similarly in both early-stage and ultraclean samples with TSC = 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.