Magnetization,specific heat,and muon spin relaxation(μSR)experiments have been carried out on the Cr-based nitride superconductor La_(3)Cr_(10-x)N_(11),which exhibits a number of unconventional superconducting proper...Magnetization,specific heat,and muon spin relaxation(μSR)experiments have been carried out on the Cr-based nitride superconductor La_(3)Cr_(10-x)N_(11),which exhibits a number of unconventional superconducting properties.The susceptibilityχ(T)shows nearly perfect superconducting diamagnetism(4πχ(T=0)≈-1)and a remarkably high upper critical fieldμ_(0)Hc_(2)=11.2 T.The specific heat displays activated exponential behavior exp(-Δ0/kBT),together with a large and field-dependent residual Sommerfeld coefficient.Transverse-field muon spin relaxation(μSR)measurements suggest s+s-wave or p-wave pairing symmetry,ruling out single s-wave pairing.Zero-fieldμSR yields no statistically significant evidence for time reversal symmetry breaking(TRSB),and places an upper bound of 1.5(1.3)ms-1 on any TRSB-induced muon relaxation rate at T=0.Our results suggest that the unconventional superconductivity in Ln_(3)Cr_(10-x)N_(11),Ln=La and Pr,is mainly due to Cr 3d electrons and is similar in both compounds,whereas Pr 4f electrons are primarily responsible for the TRSB superconductivity observed in Pr_(3)Cr_(10-x)N_(11).展开更多
基金funded by the National Key Research and Development Program of China(Grant No.2022YFA1402203)the National Natural Science Foundations of China(Grant No.12174065)+1 种基金the Innovation Program for Quantum Science and Technology(Grant No.2024ZD0300104)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01).
文摘Magnetization,specific heat,and muon spin relaxation(μSR)experiments have been carried out on the Cr-based nitride superconductor La_(3)Cr_(10-x)N_(11),which exhibits a number of unconventional superconducting properties.The susceptibilityχ(T)shows nearly perfect superconducting diamagnetism(4πχ(T=0)≈-1)and a remarkably high upper critical fieldμ_(0)Hc_(2)=11.2 T.The specific heat displays activated exponential behavior exp(-Δ0/kBT),together with a large and field-dependent residual Sommerfeld coefficient.Transverse-field muon spin relaxation(μSR)measurements suggest s+s-wave or p-wave pairing symmetry,ruling out single s-wave pairing.Zero-fieldμSR yields no statistically significant evidence for time reversal symmetry breaking(TRSB),and places an upper bound of 1.5(1.3)ms-1 on any TRSB-induced muon relaxation rate at T=0.Our results suggest that the unconventional superconductivity in Ln_(3)Cr_(10-x)N_(11),Ln=La and Pr,is mainly due to Cr 3d electrons and is similar in both compounds,whereas Pr 4f electrons are primarily responsible for the TRSB superconductivity observed in Pr_(3)Cr_(10-x)N_(11).
