Temperature evolution of magnetic and transport behavior in 5\textit{d} Mott insulator Sr${}_2$IrO${}_4$: Significance of magneto-structural coupling

Abstract

We have investigated the temperature evolution of magnetism and its interrelation with structural parameters in perovskite-based layered compound Sr${}_2$IrO${}_4$, which is believed to be a $J_{eff}$ = 1/2 Mott insulator. The structural distortion plays an important role in this material which induces a weak ferromagnetism in otherwise antiferromagnetically ordered magnetic state with transition temperature around 240 K. Interestingly, at low temperature below around 100 K, a change in magnetic moment has been observed. Temperature dependent x-ray diffraction measurements show sudden changes in structural parameters around 100 K are responsible for this. Resistivity measurements show insulating behavior throughout the temperature range across the magnetic phase transition. The electronic transport can be described with Mott's two-dimensional variable range hopping (VRH) mechanism, however, three different temperature ranges are found for VRH, which is a result of varying localization length with temperature. A negative magnetoresistance (MR) has been observed at all temperatures in contrast to positive behavior generally observed in strongly spin-orbit coupled materials. The quadratic field dependence of MR implies a relevance of a quantum interference effect.

9 pages, 9 figures

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Cited by in corpus (8)

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• Low temperature ferromagnetism in perovskite SrIrO${}_3$ films
• Crystal structure and physical properties of the Sr-vacant spin-orbit-coupling induced Mott insulator Sr2-xIrO4
• Precise control of $J_{\mathrm{eff}}=1/2$ magnetic properties in Sr${}_2$IrO${}_4$ epitaxial thin films by variation of strain and thin film thickness
• Anisotropic Lattice Compression and Pressure-Induced Electronic Phase Transitions in Sr${}_2$IrO${}_4$
• Structural, magnetic and dielectric properties in 3$d$-5$d$ based Sr${}_2$FeIrO${}_6$ thin films
• Tuning the structural, electronic and magneto-transport properties of spin-orbit Mott insulator Sr2IrO4
• Fluorite-related iridate Pr${}_3$IrO${}_7$: Crystal growth, structure, magnetism, thermodynamic, and optical properties