Magnetic and structural properties of the iron silicide superconductor LaFeSiH

Mads Fonager Hansen (1, 2) , Samar Layek (3, 4) , Jean-Baptiste Vaney (5) , Laura Chaix (1) , Matthew R. Suchomel (5) , Mirko Mikolasek (6) , Gastón Garbarino (6) , Alexander I. Chumakov (6) , Rudolf Rüffer (6) , V. Nassif (7, 8) , Thomas Hansen (8) , Erik Elkaïm (9) , Thomas Pelletier (10) , Hadrien Mayaffre (10) , Fabio Bernardini (11) , A. Sulpice (3) , Manuel Núñez-Regueiro (3) , Pierre Rodière (3) , Andrés Cano (12) , Sophie Tencé (5) , Pierre Toulemonde (1) , Marc-Henri Julien (10) , Matteo d'Astuto (3)

1 NEEL - MRS - Matériaux, Rayonnements, Structure
2 Carnegie Observatories
3 NEEL - MagSup - Magnétisme et Supraconductivité
4 UPES - University of Petroleum and Energy Studies [Dehradun]
5 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
6 ESRF - European Synchrotron Radiation Facility [Grenoble]
7 NEEL - CRG - CRG & Grands instruments
8 ILL - Institut Laue-Langevin
9 SSOLEIL - Synchrotron SOLEIL
10 LNCMI-G - Laboratoire national des champs magnétiques intenses - Grenoble
11 UniCa - Università degli Studi di Cagliari = University of Cagliari
12 NEEL - TMC - Théorie de la Matière Condensée

The magnetic and structural properties of the recently discovered pnictogen/chalcogen-free superconductor LaFeSiH have been investigated by 57Fe synchrotron Mössbauer 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.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Mads Fonager Hansen, Samar Layek, Jean-Baptiste Vaney, Laura Chaix, Matthew R. Suchomel, et al.. Magnetic and structural properties of the iron silicide superconductor LaFeSiH. Physical Review B, 2024, 109 (17), pp.174523. ⟨10.1103/PhysRevB.109.174523⟩. ⟨hal-04214168⟩