Magnetic and structural properties of the iron silicide superconductor LaFeSiH

Hansen, M. F.;Layek, S.;Vaney, J. -B.;Chaix, L.;Suchomel, M. R.;Mikolasek, M.;Garbarino, G.;Chumakov, A.;Rüffer, R.;Nassif, V.;Hansen, T.;Elkaim, E.;Pelletier, T.;Mayaffre, H.;Bernardini, F.;Sulpice, A.;Núñez-Regueiro, M.;Rodière, P.;Cano, A.;Tencé, S.;Toulemonde, P.;Julien, M. -H.;d'Astuto, M.

2024-01-01

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Abstract

The magnetic and structural properties of the recently discovered pnictogen/chalcogen-free superconductor LaFeSiH have been investigated by 57Fe synchrotron M & ouml;ssbauer source spectroscopy, X-ray and neutron powder diffraction, and 29Si nuclear magnetic resonance spectroscopy. In contrast with earlier work suggesting the presence of an orthorhombic and magnetic ground state as in underdoped Fe -based pnictides, our results unambiguously establish that LaFeSiH is in fact similar to strongly overdoped Fe -based pnictides: there is no magnetic order (including under hydrostatic pressure up to 18.8 GPa), nor even fluctuating local moments and the system remains tetragonal down to 2 K. This raises the prospect of enhancing the Tc of LaFeSiH by reducing its carrier concentration through appropriate chemical substitutions.