High temperature spin-freezing transition in Pyrochlore Eu2Ti2O7: A new observation from ac-susceptibility

TL;DR

This study reports a novel high-temperature spin-freezing transition in Eu2Ti2O7 pyrochlore, observed through ac susceptibility, revealing slow spin relaxation and a thermally activated process linked to Eu3+ ions.

Contribution

First observation of a high-temperature spin-freezing transition in Eu2Ti2O7, attributed to single ion Eu3+ spin relaxation, confirmed by non-magnetic Y3+ dilution.

Findings

Spin freezing occurs below 35K in Eu2Ti2O7.

The spin relaxation follows the Arrhenius law.

Single ion Eu3+ process drives the freezing.

Abstract

The magnetization (both dc and ac) of pyrochlore Eu2Ti2O7 have been investigated. Ac susceptibility measurements reveal a new unusual spin freezing below 35K for pure Eu2Ti2O7. Frequency dependence of these ac peak positions indicate slow spin relaxation near this temperature and it follows the Arrhenius formula suggesting a thermally activated relaxation process. The origin of this spin freezing has been attributed essentially to a single ion process which is associated to Eu3+ spin relaxation. Non-magnetic dilution by Y3+ ions also confirms the single ion freezing.