Half metallic ferromagnetism in tri-layered perovskites Sr$_4$T$_{3}$O$_{10}$ (T=Co, Rh)

TL;DR

This study uses first-principles DFT calculations to identify Sr$_4$Rh$_3$O$_{10}$ and Sr$_4$Co$_3$O$_{10}$ as potential half-metallic ferromagnets with high spin polarization and significant magnetic moments, relevant for spintronic applications.

Contribution

It demonstrates the half-metallic ferromagnetic nature of Sr$_4$Rh$_3$O$_{10}$ and predicts a spin state transition upon Co substitution, introducing new candidate materials for spintronics.

Findings

Sr$_4$Rh$_3$O$_{10}$ is a half-metallic ferromagnet with 100% spin polarization.

Full Co substitution induces a low-spin to intermediate-spin transition, increasing magnetic moment.

Sr$_4$Rh$_3$O$_{10}$ and Sr$_4$Co$_3$O$_{10}$ are proposed as new half-metal candidates.

Abstract

First-principles density functional theory (DFT) is used to investigate the electronic and magnetic properties of Sr$_4$Rh$_3$O$_{10}$, a member of the Ruddlesden-Popper series. Based on the DFT calculations taking into account the co-operative effect of Coulomb interaction ($U$) and spin-orbit couplings (SOC), Sr$_4$Rh$_3$O$_{10}$ is found to be a half metallic ferromagnet (HMF) with total angular moment $\mu_{\rm {tot}}$=12$\mu_B$ per unit cell. The material has almost 100$\%$ spin-polarization at the Fermi level despite of sizable SOC. Replacement of Rh atom by the isovalent Co atom is considered. Upon full-replacement of Co, a low-spin to intermediate spin transition happens resulting in a HMF state with the total angular moment three-time larger (i.e. $\mu_{\rm {tot}}$=36$\mu_B$ per unit cell), compared to Sr$_4$Rh$_3$O$_{10}$. We propose Sr$_4$Rh$_3$O$_{10}$ and Sr$_4$Co$_3$O$_{10}$ as candidates of half metals.