The effects of flux creep on the magnetization curves of high-temperature superconductors are investigated numerically for Anderson-Kim model.The pinning energy at zero current density,U_(c),greatly influences the flu...The effects of flux creep on the magnetization curves of high-temperature superconductors are investigated numerically for Anderson-Kim model.The pinning energy at zero current density,U_(c),greatly influences the flux penetration process,a larger U_(c),value reults in a larger penetration field.The characteristic of the magnetization curve is also a function of U_(c).The magnetization M and ΔM increase with the increasing U_(c) and depend on the magnetic induction B,so the critical current formula based on Bean model is pot accurate,especially for high-T_(c) superconductor,for which flux creep is a large effect.展开更多
The local magnetic relaxation in superconducting slab is investigated numerically for Anderson-Kim model,U(j)=U_(c)(l-j/j_(c)),and periodic pinning potential.The relaxation of B(x,t)depends on the starting profile and...The local magnetic relaxation in superconducting slab is investigated numerically for Anderson-Kim model,U(j)=U_(c)(l-j/j_(c)),and periodic pinning potential.The relaxation of B(x,t)depends on the starting profile and the position x.It is important to note that the relaxation of B(x,t)exhibits approximate scaling law for some initial condition,showing that the relaxation rate is roughly uniform over the sample.For long time,B(x,t)is towards an asymptotic behavior independent of x.展开更多
The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from...The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from 116.3K(x=0)to 93.3K(x=0.5).The critical current also decreases with increasing x.展开更多
The high Tc superconductor LaBa_(2-x)Ca_(x)Cu_(3)O_(y) has been studied and the composition dependence of Tc examined For x=1,Tconset=94K,Tc^(R=0)=80K.The structure of this system was refined utilizing the X-ray powde...The high Tc superconductor LaBa_(2-x)Ca_(x)Cu_(3)O_(y) has been studied and the composition dependence of Tc examined For x=1,Tconset=94K,Tc^(R=0)=80K.The structure of this system was refined utilizing the X-ray powder diffraction data,and it was found that the material is isostructural with YBa_(2)Cu_(3)O_(y).展开更多
The structure,magnetic,and superconducting properties of the (Tl_(1-x)Al_(x))2Ba_(2)Ca_(2)Cu_(3)O_(y) with x=0.05,0.1,0.15,0.2 were studied.The T_(c)^(R=0) depends on whether the sample has a 222S phase structure or h...The structure,magnetic,and superconducting properties of the (Tl_(1-x)Al_(x))2Ba_(2)Ca_(2)Cu_(3)O_(y) with x=0.05,0.1,0.15,0.2 were studied.The T_(c)^(R=0) depends on whether the sample has a 222S phase structure or has a 2212 phase structure.The magnetic properties in low field were measured and discussed.展开更多
文摘The effects of flux creep on the magnetization curves of high-temperature superconductors are investigated numerically for Anderson-Kim model.The pinning energy at zero current density,U_(c),greatly influences the flux penetration process,a larger U_(c),value reults in a larger penetration field.The characteristic of the magnetization curve is also a function of U_(c).The magnetization M and ΔM increase with the increasing U_(c) and depend on the magnetic induction B,so the critical current formula based on Bean model is pot accurate,especially for high-T_(c) superconductor,for which flux creep is a large effect.
文摘The local magnetic relaxation in superconducting slab is investigated numerically for Anderson-Kim model,U(j)=U_(c)(l-j/j_(c)),and periodic pinning potential.The relaxation of B(x,t)depends on the starting profile and the position x.It is important to note that the relaxation of B(x,t)exhibits approximate scaling law for some initial condition,showing that the relaxation rate is roughly uniform over the sample.For long time,B(x,t)is towards an asymptotic behavior independent of x.
文摘The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from 116.3K(x=0)to 93.3K(x=0.5).The critical current also decreases with increasing x.
文摘The high Tc superconductor LaBa_(2-x)Ca_(x)Cu_(3)O_(y) has been studied and the composition dependence of Tc examined For x=1,Tconset=94K,Tc^(R=0)=80K.The structure of this system was refined utilizing the X-ray powder diffraction data,and it was found that the material is isostructural with YBa_(2)Cu_(3)O_(y).
文摘The structure,magnetic,and superconducting properties of the (Tl_(1-x)Al_(x))2Ba_(2)Ca_(2)Cu_(3)O_(y) with x=0.05,0.1,0.15,0.2 were studied.The T_(c)^(R=0) depends on whether the sample has a 222S phase structure or has a 2212 phase structure.The magnetic properties in low field were measured and discussed.
