Structure, magnetism and electronic properties in 3$d$-5$d$ based double perovskite (Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$

TL;DR

This study investigates how yttrium doping affects the structure, magnetism, and electronic properties of the double perovskite (Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$, revealing complex magnetic and conduction behavior changes.

Contribution

It provides detailed insights into the structural, magnetic, and electronic modifications in 3$d$-5$d$ double perovskites due to yttrium substitution, highlighting nonmonotonic property evolution.

Findings

Magnetic transition around 45 K with a weak transition near 120 K.

Insulating behavior persists across all doping levels.

Structural and electronic properties exhibit reversal for x > 0.1.

Abstract

The 3$d$-5$d$ based double perovskites are of current interest as they provide model system to study the interplay between electronic correlation ($U$) and spin-orbit coupling (SOC). Here we report detailed structural, magnetic and transport properties of doped double perovskite material (Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$ with $x$ $\leq$ 0.2. With substitution of Y, system retains its original crystal structure but structural parameters modify with $x$ in nonmonotonic fashion. The magnetization data for Sr$_2$FeIrO$_6$ show antiferromagnetic type magnetic transition around 45 K, however, a close inspection in data indicates a weak magnetic phase transition around 120 K. No change of structural symmetry has been observed down to low temperature, although the lattice parameters show sudden changes around the magnetic transitions. Sr$_2$FeIrO$_6$ shows an insulating behavior over the whole temperature range which yet does not change with Y substitution. Nature of charge conduction is found to follow thermally activated Mott's variable range hopping and power law behavior for parent and doped samples, respectively. Interestingly, evolution of structural, magnetic and transport behavior in (Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$ is observed to reverse with $x$ $>$ 0.1 which is believed to arise due to change in transition metal ionic state.