Evidence for differentiation in the iron-helicoidal-chain in GdFe$_{3}$(BO$_{3}$)$_{4}$

TL;DR

This study reveals a temperature-induced structural phase transition in GdFe3(BO3)4, showing the emergence of inequivalent iron chains at low temperature, which impacts its magnetic properties.

Contribution

It provides the first detailed structural analysis of GdFe3(BO3)4 at different temperatures, highlighting the differentiation of iron chains and its implications for magnetic behavior.

Findings

Structural phase transition at 156 K from R32 to P3_1 2_1

Identification of two inequivalent iron chains at low temperature

Insights into the relationship between structure and magnetic properties

Abstract

We report on a single-crystal X-ray structure study of $GdFe_{3}(BO_{3})_{4}$ at room temperature and at T=90 K. At room temperature $GdFe_{3}(BO_{3})_{4}$ crystallizes in a trigonal space group R32 (No. 155), the same as found for other members of iron-borate family $RFe_{3}(BO_{3})_{4}$. At 90 K the structure of $GdFe_{3}(BO_{3})_{4}$ has transformed to the space group $P3_{1}2_{1}$ (No. 152). The low-temperature structure determination gives new insight into the weakly first-order structural phase transition at 156 K and into the related Raman phonon anomalies. The discovery of two inequivalent iron chains in the low temperature structure provide new point of view on the low-temperature magnetic properties.