Spin Glass Behavior in RuSr2Gd1.5Ce0.5Cu2O10

TL;DR

This study investigates the magnetic dynamics of RuSr2Gd1.5Ce0.5Cu2O10, revealing spin glass behavior through ac susceptibility and relaxation measurements, contributing to understanding its complex magnetic state.

Contribution

The paper provides evidence of spin glass behavior in Ru-1222 using ac susceptibility and relaxation studies, clarifying the magnetic nature of this magneto-superconductor.

Findings

Frequency-dependent cusp in ac susceptibility indicates spin glass transition.

Cusp position follows Vogel-Fulcher law, suggesting interacting magnetic clusters.

TRM relaxation exhibits aging effects and fits stretched exponential model.

Abstract

The dynamics of the magnetic properties of polycrystalline RuSr2Gd1.5Ce0.5Cu2O10 (Ru-1222) have been studied by ac susceptibility and dc magnetization measurements, including relaxation and ageing studies. Ru-1222 is a reported magneto-superconductor with Ru spins magnetic ordering at temperatures near 100 K and superconductivity in Cu-O2 planes below Tc ~ 40 K. The exact nature of Ru spins magnetic ordering is still debated and no conclusion has been reached yet. In this work, a frequency-dependent cusp was observed in ac susceptibility vs. T measurements, which is interpreted as a spin glass transition. The change in the cusp position with frequency follows the Vogel-Fulcher law, which is commonly accepted to describe a spin glass with magnetically interacting clusters. Such interpretation is supported by themoremanaent magnetization (TRM) measurements at T = 60 K. TRM relaxations are well described by a stretched exponential relation, and present significant ageing effects.