Some high T_c superconductors REBa_2Cu_3O_(7-x)(RE=Sm,Eu,Gd,Dy,Ho,Er,Tm) with zero resist- ance temperatures were about 90K have been prepared.The effect of magnetic rare earth ions on the transi- tion temperatures is...Some high T_c superconductors REBa_2Cu_3O_(7-x)(RE=Sm,Eu,Gd,Dy,Ho,Er,Tm) with zero resist- ance temperatures were about 90K have been prepared.The effect of magnetic rare earth ions on the transi- tion temperatures is not very great,but their magnetic behaviours are different from each other.The magnetization loops of these compounds have been measured at 77K.The coexistence of superconductivity with magnetic ordering (COSM) found in the samples with RE=Gd,Dy,Ho,Er,Tm,indicates that there are two possible ways of coexistence in the samples.These expertments show that the relation of paramagnetism to the atomtc number of rare earth elements for these superconductors is similar to that of rare earth ions in some paramagnetic salt crystals,which indicates that the magnetism of the samples origi- nates from the local magnetic moments of rare earth ions.In some samples there is antiferromagnetie ordering at low temperatures,and the effective Bohr magneton numbers are consistent with that of free rare earth ions. Some superconducting parameters including the critical current density are calculated according to Ginzburg-Landau theory and the critical state model.展开更多
The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain ...The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.展开更多
The high temperature superconducting REBa2 Cu3 O7-x(REBCO)bulk with a diameter of only a few centimeters can trap a tesla⁃level magnetic field at a moderate temperature.The high magnetic field in such a compact struct...The high temperature superconducting REBa2 Cu3 O7-x(REBCO)bulk with a diameter of only a few centimeters can trap a tesla⁃level magnetic field at a moderate temperature.The high magnetic field in such a compact structure makes the REBCO bulk magnet widely applicable in many scenarios,such as in motor,generator,and bearing for flywheel.This review focuses on some research areas using the REBCO bulk magnet,which is quite interesting but has attracted little attention,including magnet lens,compact NMR,magnetron sputtering system,drug magnetic targeting system,magnetic separation,and magnetic mirror.In all of these areas,the REBCO bulk magnet shows its own advantages of having a high magnetic field but a small size to improve the final function.展开更多
基金Supported by the Chinese National Science Foundation and originally published in J.Chin.RE Soc.(Chin.ed.),1989,7(2),63.
文摘Some high T_c superconductors REBa_2Cu_3O_(7-x)(RE=Sm,Eu,Gd,Dy,Ho,Er,Tm) with zero resist- ance temperatures were about 90K have been prepared.The effect of magnetic rare earth ions on the transi- tion temperatures is not very great,but their magnetic behaviours are different from each other.The magnetization loops of these compounds have been measured at 77K.The coexistence of superconductivity with magnetic ordering (COSM) found in the samples with RE=Gd,Dy,Ho,Er,Tm,indicates that there are two possible ways of coexistence in the samples.These expertments show that the relation of paramagnetism to the atomtc number of rare earth elements for these superconductors is similar to that of rare earth ions in some paramagnetic salt crystals,which indicates that the magnetism of the samples origi- nates from the local magnetic moments of rare earth ions.In some samples there is antiferromagnetie ordering at low temperatures,and the effective Bohr magneton numbers are consistent with that of free rare earth ions. Some superconducting parameters including the critical current density are calculated according to Ginzburg-Landau theory and the critical state model.
基金Supported by the National Natural Science Foundation of China under Grant No 11372096the Research Fund for the Doctoral Program of Higher Education of China
文摘The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.
基金National Key R&D Program of China(Grant No.2018YFF0109401)the National Natural Science Foundation of China(Grant Nos.51702316,51777205,51807191 and 11745005)+1 种基金the International Partnership Program of the Chinese Academy of Sciences(Grant Nos.182111KYSB20170039 and 182111KYSB20170067)the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS⁃LY⁃JSC039).
文摘The high temperature superconducting REBa2 Cu3 O7-x(REBCO)bulk with a diameter of only a few centimeters can trap a tesla⁃level magnetic field at a moderate temperature.The high magnetic field in such a compact structure makes the REBCO bulk magnet widely applicable in many scenarios,such as in motor,generator,and bearing for flywheel.This review focuses on some research areas using the REBCO bulk magnet,which is quite interesting but has attracted little attention,including magnet lens,compact NMR,magnetron sputtering system,drug magnetic targeting system,magnetic separation,and magnetic mirror.In all of these areas,the REBCO bulk magnet shows its own advantages of having a high magnetic field but a small size to improve the final function.
