Magnetic Properties under Pressure in Novel Spin-Triplet Superconductor UTe2

• Published in: Journal of the Physical Society of Japan 2021-07, Vol.90 (7)
• Main Authors: Li, Dexin, Nakamura, Ai, Honda, Fuminori, Sato, Yoshiki J, Homma, Yoshiya, Shimizu, Yusei, Ishizuka, Jun, Yanase, Youichi, Knebel, Georg, Flouquet, Jacques, Aoki, Dai
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Axes (reference lines); Critical pressure; Fermi surfaces; Ferromagnetism; Low pressure; Low temperature; Magnetic anomalies; Magnetic permeability; Magnetic properties; Magnetism; Magnetization; Short range order
• ISSN: 0031-9015; 1347-4073
• DOI: 10.7566/JPSJ.90.073703

We report the magnetic susceptibility and the magnetization under pressures up to 1.7 GPa above the critical pressure, Pc ∼ 1.5 GPa, for H || a, b, and c-axes in the novel spin triplet superconductor UTe2. The anisotropic magnetic susceptibility at low pressure with the easy magnetization a-axis changes to the quasi-isotropic behavior at high pressure, revealing a rapid suppression of the susceptibility for a-axis, and a gradual increase of the susceptibility for the b-axis. At 1.7 GPa above Pc, magnetic anomalies are detected at TMO ∼ 3 K and TWMO ∼ 10 K. The former anomaly corresponds to long-range magnetic order, most likely antiferromagnetism, while the latter shows a broad anomaly, which is probably due to the development of short range order. The unusual decrease and increase of the susceptibility below TWMO for H || a and b-axes, respectively, indicate the complex magnetic properties at low temperatures above Pc. This is related to the interplay between multiple fluctuations dominated by antiferromagnetism, ferromagnetism, valence and Fermi surface instabilities.