Computer predictions on Rh-based double perovskites with unusual electronic and magnetic properties

Anita Halder,Dhani Nafday,Tanusri Saha-Dasgupta,Prabuddha Sanyal

doi:10.1038/s41535-018-0091-6

Abstract

In search for new magnetic materials, we make computer prediction of structural, electronic and magnetic properties of yet-to-be synthesized Rh-based double perovskite compounds, Sr(Ca)2BRhO6 (B=Cr, Mn, Fe). We use combination of evolutionary algorithm, density functional theory, and statistical–mechanical tool for this purpose. We find that the unusual valence of Rh5+ may be stabilized in these compounds through formation of oxygen ligand hole. Interestingly, while the Cr–Rh and Mn–Rh compounds are predicted to be ferromagnetic half-metals, the Fe–Rh compounds are found to be rare examples of antiferromagnetic and metallic transition-metal oxide with three-dimensional electronic structure. The computed magnetic transition temperatures of the predicted compounds, obtained from finite temperature Monte Carlo study of the first principles-derived model Hamiltonian, are found to be reasonably high. The prediction of favorable growth condition of the compounds, reported in our study, obtained through extensive thermodynamic analysis should be useful for future synthesize of this interesting class of materials with intriguing properties.

Highlights

While magnetic materials are technologically important and useful in every day life, they are rare
Keeping in mind the cost and effort involved in synthesizing new materials, prediction of new materials with a focused need by computation is becoming increasingly popular among the researchers
In this study we consider the case of yet-tosynthesized Rh family of magnetic double perovskite (DP), namely Sr(Ca)2BRhO6, where B is Cr or Mn or Fe

Summary

Introduction

While magnetic materials are technologically important and useful in every day life, they are rare. In this study we will focus on the computer prediction of new double perovskite (DP) compounds, which pose the promise of exhibiting novel electronic and magnetic properties. These compounds have a general formula of A2BB′O6, where A site is occupied by alkaline-earth or rare-earth ions, and B and B′ sites are occupied by transition metal (TM) elements. Some of the magnetic members of this family are well-known for their spectacularly high magnetic transition temperature, like Sr2FeMoO6,4 Sr2CrMoO6,5,6 Sr2CrWO6,7 Sr2CrReO6,8 or Sr2CrOsO6.9 Due to the presence of two TM elements (B and B′) in DP, instead of one B element as in simple perovskites, DPs provide large flexibility in choice of different combinations of B and B′, leading to possible engineering of novel magnetic properties. Possible predictions can be made on a large number of new DP compounds, that has remained unexplored so far

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