Low temperature magnetic transition in RuSr2EuCeCu2O10 ruthenocuprate

TL;DR

This study reports a new low-temperature magnetic transition in RuSr2EuCeCu2O10, characterized by ac susceptibility and magnetization measurements, indicating superparamagnetic behavior and intrinsic properties of the compound.

Contribution

It identifies a previously unobserved magnetic transition in RuSr2EuCeCu2O10 and links it to superparamagnetic dynamics, highlighting its intrinsic nature compared to similar compositions.

Findings

Magnetic transition occurs below 10 K as a kink in ac susceptibility

Transition shows frequency dependence consistent with Arrhenius law

No similar transition observed in RuSr2Eu1.1Ce0.9Cu2O10

Abstract

A new magnetic transition in the ruthenocuprate parent compound RuSr2EuCeCu2O10 has been observed below 10 K. It shows up only as a kink in the imaginary part of the ac susceptibility and exhibits a pronounced frequency dependence. At the same time, the real part of the ac susceptibility and the dc magnetization study show very little change in the same temperature window suggesting only a minor fraction of the material to be involved in the transition. Frequency dependence shows excellent agreement with the predictions of the Arrhenius law known to describe well the dynamics of the superparamagnetic particles. The same type of the investigation on the RuSr2Eu1.1Ce0.9Cu2O10 composition showed no evidence of the similar transition, which points to a possible intrinsic behavior.