We report the solution fabrication of a MgB2 coated conductor on a stainless steel substrate.The precursor solution of Mg(BH_(4))^(2) diethyl ether is initially synthesized by refluxing the milled mixture of NaBH4 and...We report the solution fabrication of a MgB2 coated conductor on a stainless steel substrate.The precursor solution of Mg(BH_(4))^(2) diethyl ether is initially synthesized by refluxing the milled mixture of NaBH4 and MgCl_(2) in diethyl ether.Then the Mg(BH4)2 diethyl ether is spin coated on a stainless steel substrate and annealed in Mg vapor,which yields a homogeneous MgB_(2) coated conductor.X-ray diffraction indicates that the grown MgB_(2) coated conductor is polycrystalline.It has a superconducting transition temperature of 34-37K.The slope of the upper critical field HC_(2) increases with decreasing temperature,and the extrapolated value of Hc2 (0)reaches ~28 T.The critical current density estimated by the Bean model is JC (25K,0 T)~1 06 A.cm^(-2).These parameters indicate that the solution method is potentially able to produce MgB_(2) coated conductors that can satisfy application purposes.展开更多
We observed in Y-doped Bi_(2)Sr_(2)CaCu_(2)O_(y) superconductors an interesting phenomenon,the T_(c)(onset)of the Y-doped samples is highcr,but the T_(c)(end)is lower than thatof Y-free sanples.After annealing in N_(2...We observed in Y-doped Bi_(2)Sr_(2)CaCu_(2)O_(y) superconductors an interesting phenomenon,the T_(c)(onset)of the Y-doped samples is highcr,but the T_(c)(end)is lower than thatof Y-free sanples.After annealing in N_(2) atmosphere,the Te(end)is increased,butthe T_(c)e(onset)is hardly changed.Aftcr careful studying,by structure analysis,x-ray photoelectron spectroscopy,R-T relationship measurement,and Hall effect,we successfully distinguish the different factors that dominate the superconductivity,of which one is carrier concentration,others may possibly be structure change andcharges redistribution.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2006CD601004 and 2011CB605904.
文摘We report the solution fabrication of a MgB2 coated conductor on a stainless steel substrate.The precursor solution of Mg(BH_(4))^(2) diethyl ether is initially synthesized by refluxing the milled mixture of NaBH4 and MgCl_(2) in diethyl ether.Then the Mg(BH4)2 diethyl ether is spin coated on a stainless steel substrate and annealed in Mg vapor,which yields a homogeneous MgB_(2) coated conductor.X-ray diffraction indicates that the grown MgB_(2) coated conductor is polycrystalline.It has a superconducting transition temperature of 34-37K.The slope of the upper critical field HC_(2) increases with decreasing temperature,and the extrapolated value of Hc2 (0)reaches ~28 T.The critical current density estimated by the Bean model is JC (25K,0 T)~1 06 A.cm^(-2).These parameters indicate that the solution method is potentially able to produce MgB_(2) coated conductors that can satisfy application purposes.
文摘We observed in Y-doped Bi_(2)Sr_(2)CaCu_(2)O_(y) superconductors an interesting phenomenon,the T_(c)(onset)of the Y-doped samples is highcr,but the T_(c)(end)is lower than thatof Y-free sanples.After annealing in N_(2) atmosphere,the Te(end)is increased,butthe T_(c)e(onset)is hardly changed.Aftcr careful studying,by structure analysis,x-ray photoelectron spectroscopy,R-T relationship measurement,and Hall effect,we successfully distinguish the different factors that dominate the superconductivity,of which one is carrier concentration,others may possibly be structure change andcharges redistribution.
