Coexistence of Superconductivity and Magnetism in the Tm-Based Reentrant Superconductor Tm₅Rh₆Sn₁₈

Abstract

We report here the magnetic properties of the thulium-based reentrant superconductor Tm₅Rh₆Sn₁₈ (T_c=2.2 K), which were determined by magnetization and μSR measurements. The spontaneous oscillation signal in the μSR spectra gradually develops under zero magnetic field below 13 K. The development of a quasi-static local magnetic field is also observed even below T_c, indicating the coexistence of magnetism and superconductivity at zero magnetic field. From the analysis of longitudinal μSR measurements, magnetic ordering can be considered to be not truly long range but superparamagnetic.