TY - JOUR
T1 - Two-dimensional frustrated magnetic state in superconducting RuSr2 Eu1.5 Ce0.5 Cu2 O10
AU - Garcia, S.
AU - Ghivelder, L.
AU - Felner, I.
PY - 2009/2/2
Y1 - 2009/2/2
N2 - In this paper we investigate the magnetic state and the role of the crystalline structure in RuSr2 Eu1.5 Ce0.5 Cu2 O10 (Ru-1222). Measurements were made in the isomorphic series (Nb1-x Rux) Sr2 Eu1.5 Ce0.5 Cu2 O10 [(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 (τ/ τ0) =A (T- T0) -B, yields B=2.0, in excellent agreement with Monte Carlo simulations for two-dimensional (2D) systems. The value deduced for T0 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.
AB - In this paper we investigate the magnetic state and the role of the crystalline structure in RuSr2 Eu1.5 Ce0.5 Cu2 O10 (Ru-1222). Measurements were made in the isomorphic series (Nb1-x Rux) Sr2 Eu1.5 Ce0.5 Cu2 O10 [(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 (τ/ τ0) =A (T- T0) -B, yields B=2.0, in excellent agreement with Monte Carlo simulations for two-dimensional (2D) systems. The value deduced for T0 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.
UR - http://www.scopus.com/inward/record.url?scp=61549097211&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.79.054506
DO - 10.1103/PhysRevB.79.054506
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AN - SCOPUS:61549097211
SN - 1098-0121
VL - 79
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 5
M1 - 054506
ER -