Intergranular pinning potential and critical current in the magnetic superconductor RuSr2Gd1.5Ce0.5Cu2O10

M. G. das Virgens; S. García; M. A. Continentino; L. Ghivelder

doi:10.1103/PhysRevB.71.064520

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Intergranular pinning potential and critical current in the magnetic superconductor RuSr2Gd1.5Ce0.5Cu2O10

M. G. das Virgens, S. García, M. A. Continentino, L. Ghivelder

DOI 10.1103/PhysRevB.71.064520 · Physical Review B

T1

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Abstract

The intergranular pinning potential U and the critical current density JC for polycrystalline RuSr2Gd1.5Ce0.5Cu2O10 ruthenate-cuprate were determined at zero magnetic field and temperature through the frequency shift in the peak of the imaginary part of the ac magnetic susceptibility, χ″. A critical state model, including a flux creep term, was found to accurately describe the χ″ behavior. The obtained values, U(H=0,T=0)≅30meV and JC(H=0,T=0)≅110A∕cm2 are about two orders of magnitude and four times lower, respectively, in comparison with the high-TC cuprate YBa2Cu3O7. These results were ascribed to the effects of the Ru magnetization on the connectivity of the weak-linked network, giving an intrinsic local field at the junctions of ∼15Oe. The impact on JC is less intense because of the small average grain radius (∼1μm). The intragranular London penetration length at T=0[λL(0)≅2μm] was derived using a Kim-type expression for the field dependence of JC. A possible source for the large value of λL in comparison to the high-Tc cuprates is suggested to come from a strong intragrain granularity, due to structural domains of coherent-rotated RuO6 octahedra separated by antiphase boundaries.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
RuSr2Gd1.5Ce0.5Cu2O10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22	Pressure not reported	onset
YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown