Sulfur-induced magnetism in FeSe1-xSx thin films on LaAlO3 revealed by muon spin rotation/relaxation

Muon spin rotation/relaxation measurements were performed to investigate magnetic properties of FeSe1-xSx thin films on LaAlO3. A drastic decrease of the initial asymmetry was observed together with the peak structure in the temperature dependence of the relaxation rate of muon spins almost at the same temperature where kink anomalies were observed in the temperature-dependent resistivity. With increasing S content, the anomaly temperature increased and the magnetic fluctuations at the lowest temperature were suppressed. These results show that the S substitution induces magnetism at low temperatures in FeSe1-xSx thin films. Although the behaviors of the magnetic and nematic phases in FeSe films toward chemical pressure by S substitution are similar to those for bulk FeSe toward hydrostatic pressure, the behavior of T-c is significantly different between these systems. Our results demonstrate that the detailed comparative investigation among physical and chemical pressure effects is essentially important to understand the interplay of the magnetism, the nematicity, and the superconductivity in iron chalcogenides.

Automated summary

Muon spin rotation/relaxation measurements were used to investigate the magnetic properties of FeSe1-xSx thin films on LaAlO3. The results show that S substitution induces magnetism at low temperatures in the films, with the anomaly temperature increasing and magnetic fluctuations being suppressed with increasing S content. The behavior of Tc is significantly different between the FeSe films under chemical pressure from S substitution compared to bulk FeSe under hydrostatic pressure.