Two dimensional frustrated magnetic state in superconducting RuSr2Eu1.5Ce0.5Cu2O10 (Ru-1222)

TL;DR

This study reveals a two-dimensional frustrated magnetic state in RuSr2Eu1.5Ce0.5Cu2O10, characterized by weak inter-plane coupling and cluster-glass behavior, with magnetic dynamics consistent with 2D Monte Carlo simulations.

Contribution

It provides new insights into the 2D magnetic frustration and glassy behavior in Ru-1222, highlighting the role of crystalline structure and compositional effects.

Findings

Weak inter-plane coupling in Ru-1222.

Cluster-glass magnetic state with 2D characteristics.

Magnetic dynamics fit a generalized Vogel-Fulcher dependence.

Abstract

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 x between 0 and 1. 3D XY fluctuations above the magnetic transition were not observed in Ru-1222, suggesting a weak inter-plane 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 of 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/tau0) = A(T-T0)^-B, yield B = 2.0, in excellent agreement with Monte Carlo simulations for 2D systems. The value deduced for T0 agrees well with the re-opening 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.