Nuclear magnetic resonance on $LaFeAsO_{0.4}H_{0.6}$ at 3.7 GPa

N. Fujiwara; M. Takeuchi; T. Kuwayama; S. Nakagawa; S. Iimura; S. Matsuishi; H. Hosono

doi:10.4279/pip.110002

Authors

N. Fujiwara Graduate School of Human and Environmental Studies, Kyoto University
M. Takeuchi Graduate School of Human and Environmental Studies, Kyoto University
T. Kuwayama Graduate School of Human and Environmental Studies, Kyoto University
S. Nakagawa Graduate School of Human and Environmental Studies, Kyoto University
S. Iimura Institute for Innovative Research, Tokyo Institute of Technology
S. Matsuishi Materials Research Center for Element Strategy, Tokyo Institute of Technology
H. Hosono Institute for Innovative Research, Tokyo Institute of Technology - Materials Research Center for Element Strategy, Tokyo Institute of Technology

DOI:

https://doi.org/10.4279/pip.110002

Keywords:

NMR, high pressure, iron pnictide, superconductor

Abstract

A prototypical electron-doped iron-based superconductor $LaFeAsO_{1-x}H_x$ undergoes an antiferromagnetic (AF) phase for $x \geq 0.49$. We performed NMR measurements on $LaFeAsO_{0.4}H_{0.6}$ at 3.7 GPa to investigate the magnetic properties in the vicinity of a pressure-induced QCP. The linewidth of $~^1H$-NMR spectra broadens at low temperatures below 30 K, suggesting that the ordered spin moments remain at 3.7 GPa. The coexistence of gapped and gapless spin excitations was confirmed in the ordered state from the relaxation time $T_1$ of $~^{75}As$. The pressure-induced QCP is estimated to be 4.1 GPa from the pressure dependence of the gapped excitation.

Edited by: A. Goñi, A. Cantarero, J. S. Reparaz