Superconductivity in Mg-Doped Layered Intermetallic Compound NbB2
LIU Guang-Tong1,2, JIN Hao2, LI Zheng1, GENG Hong-Xia1, CHE Guang-Can1, JIN Duo1, SUN Lian-Feng2 XIE Si-Shen1, LUO Jian-Lin1
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 1000802National Center for Nanoscience and Technology, Beijing 100080
Superconductivity in Mg-Doped Layered Intermetallic Compound NbB2
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 1000802National Center for Nanoscience and Technology, Beijing 100080
摘要We have performed low temperature resistivity ρ(T) and specific heat C(T) measurements on a superconducting polycrystalline Nb0.75Mg0.25B2 sample. The results indicate that the superconducting transition temperature is ~4.6K. The zero temperature upper critical field determined from the resistivity and specific heat is 3123Oe. The electronic coefficient of specific heat γn=4.51mJmol-1K2 and the Debye temperature θD=419K are obtained by fitting the zero-field specific heat data in the normal state. At low temperatures, the electronic specific heat in the superconducting state follows CesθnTc=2.84exp(1.21Tc/T). This indicates that the superconducting pairing in Nb0.75Mg0.25B2 has s-wave symmetry.
Abstract：We have performed low temperature resistivity ρ(T) and specific heat C(T) measurements on a superconducting polycrystalline Nb0.75Mg0.25B2 sample. The results indicate that the superconducting transition temperature is ~4.6K. The zero temperature upper critical field determined from the resistivity and specific heat is 3123Oe. The electronic coefficient of specific heat γn=4.51mJmol-1K2 and the Debye temperature θD=419K are obtained by fitting the zero-field specific heat data in the normal state. At low temperatures, the electronic specific heat in the superconducting state follows CesθnTc=2.84exp(1.21Tc/T). This indicates that the superconducting pairing in Nb0.75Mg0.25B2 has s-wave symmetry.
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