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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Two-dimensional frustrated magnetic state in superconducting RuSr2Eu1.5Ce0.5Cu2O10

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Garcia, S. [1, 2] ; Ghivelder, L. [1] ; Felner, I. [3]
Total Authors: 3
[1] Univ Fed Rio de Janeiro, Inst Fis, BR-21941972 Rio De Janeiro - Brazil
[2] Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo - Brazil
[3] Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem - Israel
Total Affiliations: 3
Document type: Journal article
Source: Physical Review B; v. 79, n. 5 FEB 2009.
Web of Science Citations: 7

In this paper we investigate the magnetic state and the role of the crystalline structure in RuSr2Eu1.5Ce0.5Cu2O10 (Ru-1222). Measurements were made in the isomorphic series (Nb1-xRux)Sr2Eu1.5Ce0.5Cu2O10 {[}(Nb,Ru)-1222], with 0 <= x <= 1. Three-dimensional (3D) XY fluctuations above the magnetic transition were not observed in Ru-1222, suggesting a weak interplane coupling between the RuO2 layers. The compositional dependence of the magnetic susceptibility shows a rapid broadening with increasing Nb content, explained in terms of a cluster-glass state. The variation in several superconducting parameters as a function of Ru content is linear in the whole concentration range, with no jumps at the critical concentration for which percolation of long-range order is expected. 3D Arrhenius- and Vogel-Fulcher-type dependencies fail to describe the dynamic properties. Fitting of a generalized Vogel-Fulcher-type dependence, with ln(tau/tau(0)) = A(T-T-0)(-B), yields B = 2.0, in excellent agreement with Monte Carlo simulations for two-dimensional (2D) systems. The value deduced for T-0 agrees well with the reopening of hysteresis in the M(H) curves. The observed superconducting and magnetic features are explained in terms of a scenario of 2D magnetic islands at the RuO2 layers, with no long-range magnetic order. (AU)