Structure symmetry determination and magnetic evolution in $\rm Sr_2Ir_{1-x}Rh_{x}O_4$

TL;DR

This study investigates how Rh doping affects the crystal symmetry and magnetic properties of Sr2IrO4, revealing structural stability and magnetic suppression with doping, and a change in magnetic structure at intermediate doping levels.

Contribution

It provides detailed neutron diffraction analysis showing the preservation of tetragonal symmetry and the evolution of magnetic order in Rh-doped Sr2IrO4, highlighting new magnetic structures at specific doping levels.

Findings

Crystal structure remains tetragonal with space group I4_1/a across doping range.

Magnetic moments decrease with Rh doping, from 0.21 to 0.18 μ_B/Ir.

Magnetic structure changes at x=0.12, with moments in the basal plane.

Abstract

We use single-crystal neutron diffraction to determine the crystal structure symmetry and the magnetic evolution in the rhodium doped iridates $\rm Sr_2Ir_{1-x}Rh_{x}O_4$ ($0\leq x \leq 0.16$). Throughout this doping range, the crystal structure retains a tetragonal symmetry (space group $I4_1/a$) with two distinct magnetic Ir sites in the unit cell forming staggered $\rm IrO_6$ rotation. Upon Rh doping, the magnetic order is suppressed and the magnetic moment of Ir$^{4+}$ is reduced from 0.21 $\rm \mu_B$/Ir for $x=0$ to 0.18 $\rm \mu_B$/Ir for $x=0.12$. The magnetic structure at $x=0.12$ is different from that of the parent compound while the moments remain in the basal plane.