Unveiling the magnetic ground states in the iridate double perovskite Pr(2-x)SrxMgIrO6 (x = 0 and 0.5) series

TL;DR

This study investigates the magnetic ground states of Pr(2-x)SrxMgIrO6 double perovskites using magnetic, thermodynamic, and neutron diffraction techniques, revealing antiferromagnetic transitions and ordering in both compounds.

Contribution

It provides detailed experimental insights into the magnetic ordering and ground states of Pr(2-x)SrxMgIrO6 compounds, including neutron diffraction analysis and charge state confirmation.

Findings

Pr2MgIrO6 exhibits AFM transition at 14.5 K.

Pr1.5Sr0.5MgIrO6 shows AFM transition at 6 K.

Both compounds have AFM ordering with propagation vector k = (1/2, 0, 1/2).

Abstract

We report here the results of a detailed magnetic, thermodynamic, and neutron powder diffraction (NPD) studies carried out on the double perovskite iridates Pr(2-x)SrxMgIrO6 (x = 0 and 0.5). Temperature dependent bulk DC susceptibility data clearly reveals a sharp antiferromagnetic (AFM) transition at 14.5 K in Pr2MgIrO6(x = 0). Next, a weaker signature of an AFM transition at a lower temperature (6 K) is observed in x = 0.5 i.e., Pr1.5Sr0.5MgIrO6 (PSMIO1505). The observed magnetic transitions are further corroborated by the presence of anomalies around the same temperatures in our T-dependent specific heat results. The charge states of both Pr and Ir cations have been confirmed to be the expected ones (3+ for Pr in both the compounds, while Ir is in a pure 4+ state for x = 0 and in a mixed 4+/5+ state for x = 0.5) from the core-level x-ray photoemission spectroscopy (XPS) measurements. Using neutron powder diffraction (NPD) the magnetic ground states and the magnetic moment values were determined for both compounds. Both the Pr- and Ir-sites undergo AFM ordering below the respective transition temperatures, designated by the propagation vector k = ( 1/2 , 0, 1/2 ), in both the compounds.