Magnetism and electrical transport in Y-doped layered iridate Sr$_2$IrO$_4$

TL;DR

This study explores how Y-doping in Sr$_2$IrO$_4$ affects its structural, magnetic, and electronic properties, revealing minimal changes in magnetic state and a 2D hopping conduction mechanism, with complex magnetoresistance behavior.

Contribution

It provides new insights into electron doping effects in Sr$_2$IrO$_4$ without altering key parameters like SOC and electron correlation.

Findings

Charge conversion from Ir$^{4+}$ to Ir$^{3+}$ with Y-doping.

Magnetoresistance sign change with temperature and magnetic field.

Conduction follows a 2D hopping model across the series.

Abstract

Here, we report an investigation of structural, magnetic and electronic properties in Y-doped layered iridate (Sr$_{1-x}$Y$_x$)$_2$IrO$_4$ ($x$ $\leq$ 0.1). The parent Sr$_2$IrO$_4$ is a well-studied spin-orbit coupling (SOC) induced insulator with an antiferromagnetic ground state. The Y-doping here equivalently acts for electron doping without altering the vital parameters such as, SOC and electron correlation. Experimental results show a minute change in structural parameters and an equivalent charge conversion from Ir$^{4+}$ to Ir$^{3+}$. Unlike similarly other electron-doped system, the low temperature magnetic and electronic state in present series is minimally influenced. The charge conduction mechanism follows 2-dimensional hopping model in whole series. Magnetoresistance (MR) data show an interesting sign change with both temperature and magnetic field. The positive MR both at low temperature follows weak antilocalization behavior where the sign change in MR is believed to be caused by an interplay between SOC and magnetic moment.