Reentrant spin glass transition in LuFe2O4

TL;DR

This study investigates the magnetic phase transitions in LuFe2O4, revealing a paramagnetic to ferrimagnetic transition at 236 K and a reentrant spin glass phase below 228 K, with detailed analysis of magnetic relaxation and aging effects.

Contribution

The paper provides the first comprehensive magnetic characterization of LuFe2O4, identifying a reentrant spin glass phase through AC susceptibility and dynamic scaling analysis.

Findings

Paramagnetic to ferrimagnetic transition at ~236 K

Reentrant spin glass phase below ~228 K

Evidence of aging, memory, and rejuvenation effects

Abstract

We have carried out a comprehensive investigation of magnetic properties of LuFe$_2$O$_4$, using AC susceptibility, DC magnetization and specific heat. A magnetic phase transition around $\sim$236 K was observed with DC magnetization and specific heat measurements, which is identified as a paramagnetic to ferrimagnetic transition based on the nonlinear susceptibility data. Upon further cooling below this temperature, we also observed highly relaxational magnetic behavior: the DC magnetization exhibits history and time dependence, and the real and imaginary part of the AC susceptibility shows large frequency dependence. Dynamic scaling of the AC susceptibility data suggests that this low temperature phase can be described as a reentrant spin glass phase. We also discuss magnetic field dependence of the spin glass transition and aging, memory and rejuvenation effect below the glass transition temperature around 228 K.