I-V curves and intergranular flux creep activation energy in the magnetic superconductor RuSr2GdCu2O8

Abstract

A systematic study of I-V characteristic curves for RuSr2GdCu2O8 [Ru-(1212)] is presented, with magnetic fields up to 3 T and 5 K<T<30 K, in the region of the superconducting transition. The activation energy E_{a}(H,T) for flux line depinning was determined by fitting the nonlinear region of the curves using the flux creep model. E_{a}(H,T) was found to vary linearly with temperature, while a power-law dependence on the magnetic field was observed up to H=0.1 T, where an abrupt reduction in its decreasing rate occurs. The extrapolated value, E_{a}(0,0)=50 meV, is twice the reported value for YBa2Cu3O7, but the critical current density J_{C}(0,0)=70 A/cm2 is about one order of magnitude lower. These results are explained as a consequence of the contribution of the magnetization in the grains to the effective field at the intergranular links and to a spin-flop transition of the Ru-sub-lattice.

arXiv comment4 pages, 3 figures

References in corpus (4)

• Decoupled CuO_2 and RuO_2 layers in superconducting and magnetically ordered RuSr_2GdCu_2O_8
• Magneto-transport study of intra- and intergrain transitions in the magnetic superconductors RuSr2GdCu2O8 and RuSr2(Gd1.5Ce0.5)Cu2O10
• The Superconductivity, Intragrain Penetration Depth and Meissner Effect of RuSr2(Gd,Ce)2Cu2O10+delta
• A Transport and Microwave Study of Superconducting and Magnetic RuSr2EuCu2O8

Cited by in corpus (4)

• The Ruthenocuprates - Natural Superconductor-Ferromagnet Multilayers
• Critical fields and spontaneous vortex state in the weak-ferromagnetic superconductor RuSr2GdCu2O8
• Lower critical field and intragrain critical current density in the ruthenate-cuprate RuSr${}_2$Gd${}_{1.5}$Ce${}_{0.5}$Cu${}_2$O${}_{10}$
• Intergranular pinning potential and critical current in the magnetic superconductor RuSr2Gd1.5Ce0.5Cu2O10