Drastic change in magnetic anisotropy of UTe2 under pressure revealed by 125Te-NMR

Katsuki Kinjo; Hiroki Fujibayashi; Genki Nakamine; Shunsaku Kitagawa; Kenji Ishida; Yo Tokunaga; Hironori Sakai; Shinsaku Kambe; Ai Nakamura; Yusei Shimizu; Yoshiya Homma; Dexin Li; Fuminori Honda; Dai Aoki

doi:10.1103/physrevb.105.l140502

arXiv · 2203.12934

Drastic change in magnetic anisotropy of UTe2 under pressure revealed by 125Te-NMR

Katsuki Kinjo·Hiroki Fujibayashi·Genki Nakamine·Shunsaku Kitagawa·Kenji Ishida·Yo Tokunaga·Hironori Sakai·Shinsaku Kambe·Ai Nakamura·Yusei Shimizu·Yoshiya Homma·Dexin Li·Fuminori Honda·Dai Aoki

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Abstract

To investigate the normal-state magnetic properties of UTe2 under pressure, we perform 125Te nuclear magnetic resonance (NMR) measurements up to 2 GPa. Below 1.2 GPa, the b-axis NMR Knight shift shows a broad maximum at the so-called T_chimax on cooling, which is consistent with the magnetization measurement under pressure. T_chimax decreases with increasing pressure and disappears at the critical pressure Pc = 1.7 GPa, above which superconductivity is destroyed. This tendency is also observed in the temperature dependence of the nuclear spin-lattice relaxation rate 1/T1. At low pressures, 1/T1 shows a conventional Fermi-liquid behavior (1/T1T = constant) at low temperatures, indicating the formation of the heavy-fermion state. Above Pc, 1/T1T follows a 1/T behavior without any crossover to the heavy-fermion state down to the lowest temperature (~3 K). In addition, the NMR signals disappear below 3~K, due to the influence of the magnetically ordered moments. From the pressure dependence of the T_chimax and Knight shift, it was found that the Fermi surface character is abruptly changed at Pc, and that superconductivity is observed only in the heavy-fermion state.

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Katsuki Kinjo, Hiroki Fujibayashi, Genki Nakamine, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki. 2022-03-24. Drastic change in magnetic anisotropy of UTe2 under pressure revealed by 125Te-NMR. https://doi.org/10.1103/physrevb.105.l140502

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