Spin Glass and Semiconducting Behavior in 1D BaFe2-{\delta}Se3 Crystals

TL;DR

This study explores the electronic and magnetic properties of BaFe2-{ extdelta}Se3 crystals, revealing spin glass behavior and semiconducting characteristics, with modifications upon sulfur substitution affecting conductivity and magnetic freezing temperature.

Contribution

It provides the first detailed investigation of the spin glass and semiconducting behavior in BaFe2-{ extdelta}Se3, including effects of sulfur substitution and electronic structure analysis.

Findings

BaFe2-{ extdelta}Se3 is a semiconductor with spin glass magnetic correlations.

Sulfur substitution increases electrical conductivity and lowers spin glass freezing temperature.

Electronic structure suggests a one-dimensional ladder structure with weak interchain coupling.

Abstract

We investigate the physical properties and electronic structure of BaFe2-{\delta}Se3 crystals, which were grown out of tellurium flux. The crystal structure of the compound, an iron-deficient derivative of the ThCr2Si2-type, is built upon edge-shared FeSe4 tetrahedra fused into double chains. The semiconducting BaFe2-{\delta}Se3 with {\delta} \approx 0.2 ({\rho}295K = 0.18 {\Omega}\cdotcm and Eg = 0.30 eV) does not order magnetically, however there is evidence for short-range magnetic correlations of spin glass type (Tf \approx 50 K) in magnetization, heat capacity and neutron diffraction results. A one-third substitution of selenium with sulfur leads to a slightly higher electrical conductivity ({\rho}295K = 0.11 {\Omega}\cdotcm and Eg = 0.22 eV) and a lower spin glass freezing temperature (Tf \approx 15 K), corroborating with higher electrical conductivity reported for BaFe2S3. According to the electronic structure calculations, BaFe2Se3 can be considered as a one-dimensional ladder structure with a weak interchain coupling.