Our measurements of 125Te NMR relaxations reveal an enhancement of electronic spin fluctuations above μ0H∗∼15 T, leading to their divergence in the vicinity of the metamagnetic transition at μ0Hm≈35 T, below which field-reinforced superconductivity appears when a magnetic field (H) is applied along the crystallographic b axis. The NMR data evidence that these fluctuations are dominantly longitudinal, providing a key to understanding the peculiar superconducting phase diagram in H∥b, where such fluctuations enhance the pairing interactions.
@article{arxiv.2307.10724,
title = {Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$},
author = {Yo Tokunaga and Hironori Sakai and Shinsaku Kambe and Petr Opletal and Yoshifumi Tokiwa and Yoshinori Haga and Shunsaku Kitagawa and Kenji Ishida and Dai Aoki and Georg Knebel and Gerard Lapertot and Steffen Krämer and Mladen Horvatić},
journal= {arXiv preprint arXiv:2307.10724},
year = {2023}
}