| Texto completo | |
| Autor(es): |
Garcia, S.
;
Ghivelder, L.
;
Felner, I.
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | PHYSICAL REVIEW B; v. 79, n. 5, p. 6-pg., 2009-02-01. |
| Resumo | |
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) | |
| Processo FAPESP: | 07/51458-6 - Sergio Garcia Garcia | pessoa física - Brasil |
| Beneficiário: | Renato de Figueiredo Jardim |
| Modalidade de apoio: | Auxílio à Pesquisa - Pesquisador Visitante - Brasil |