Superconductivity （SC） is one of the most intriguing physical phenomena in nature. Nucleation of SC has long been considered highly unfavorable if not impossible near ferromagnetism, in low dimensionality and, above...Superconductivity （SC） is one of the most intriguing physical phenomena in nature. Nucleation of SC has long been considered highly unfavorable if not impossible near ferromagnetism, in low dimensionality and, above all, out of non-superconductor. Here we report observation of SC with TC near 4K in Ni/Bi bilayers that defies all known paradigms of superconductivity, where neither ferromagnetic Ni film nor rhombohedra Bi film is superconducting in isolation. This highly unusual SC is independent of the growth order （Ni/Bi or Bi/Ni）, but highly sensitive to the constituent layer thicknesses. Most importantly, the SC, distinctively non-s pairing, is triggered from, but does not occur at, the Bi/Ni interface. Using point contact Andreev reflection, we show evidences that the unique SC, naturally compatible with magnetism, is triplet p-wave pairing.展开更多
Based on the available experimental data,the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method.The solution phases,including liquid,fcc_A1（Ni） and rhombohedral_A7（Bi）,were described as subs...Based on the available experimental data,the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method.The solution phases,including liquid,fcc_A1（Ni） and rhombohedral_A7（Bi）,were described as substitutional solution phases,of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial.The intermetallic compound,BiNi,was modeled using three sublattices（Bi）（Ni,Va）（Ni,Va） considering its crystal structure（NiAs-type） and the compatibility of thermodynamic database in the multi-component systems,while Bi3Ni was treated as a stoichiometric compound.Finally,a set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in this binary system were obtained.The calculated results are in reasonable agreement with the reported experimental data.展开更多
To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223...To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223/Ag/Ni tapes were studied. The phase compositions of the samples were characterized using XRD. The microstructure was observed using SEM. Experimental results indicate that higher temperature is more conducive to the formation of Bi-2223 phase at an atmosphere of 8.5% O 2 . After the two-step heat treatment, the critical current of samples is about 67.5 A.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB921400 and 2011CB921802the National Natural Science Foundation of China under Grant Nos 11374057,11434003 and 11421404the research of Andreev reflection was supported as part of the SHINES,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science under Award SC0012670
文摘Superconductivity （SC） is one of the most intriguing physical phenomena in nature. Nucleation of SC has long been considered highly unfavorable if not impossible near ferromagnetism, in low dimensionality and, above all, out of non-superconductor. Here we report observation of SC with TC near 4K in Ni/Bi bilayers that defies all known paradigms of superconductivity, where neither ferromagnetic Ni film nor rhombohedra Bi film is superconducting in isolation. This highly unusual SC is independent of the growth order （Ni/Bi or Bi/Ni）, but highly sensitive to the constituent layer thicknesses. Most importantly, the SC, distinctively non-s pairing, is triggered from, but does not occur at, the Bi/Ni interface. Using point contact Andreev reflection, we show evidences that the unique SC, naturally compatible with magnetism, is triplet p-wave pairing.
基金Projects(50371104,50771106and50731002)supported by the National Natural Science Foundation of ChinaProject(2008K22)supported by the Scientific Research Foundation of Hunan Provincial Department of Land&Resources,ChinaProject supported by Geology Exploration Foundation of Hunan Provincial Department of Land&Resources,China
文摘Based on the available experimental data,the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method.The solution phases,including liquid,fcc_A1（Ni） and rhombohedral_A7（Bi）,were described as substitutional solution phases,of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial.The intermetallic compound,BiNi,was modeled using three sublattices（Bi）（Ni,Va）（Ni,Va） considering its crystal structure（NiAs-type） and the compatibility of thermodynamic database in the multi-component systems,while Bi3Ni was treated as a stoichiometric compound.Finally,a set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in this binary system were obtained.The calculated results are in reasonable agreement with the reported experimental data.
基金National High Technology Research and Development Program(863 program)(2009AA03Z202)Fundamental Research Funds for the Central Universities(N100423006,N110823001,N100123003)
基金financially supported by the National High Technology Research and Development Program(863program)(No.2009AA03Z202)the Fundamental Research Funds for the Central Universities(No.N100423006and No.N110823001)
文摘To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223/Ag/Ni tapes were studied. The phase compositions of the samples were characterized using XRD. The microstructure was observed using SEM. Experimental results indicate that higher temperature is more conducive to the formation of Bi-2223 phase at an atmosphere of 8.5% O 2 . After the two-step heat treatment, the critical current of samples is about 67.5 A.
