Fabrication of half metallicity in a ferromagnetic metal

TL;DR

This study demonstrates a method to induce half-metallicity in a ferromagnetic material through Ti substitution, potentially enhancing spintronic applications by enabling high spin polarization at elevated temperatures.

Contribution

The paper introduces a novel approach of Ti substitution in SrRuO3 to achieve half-metallicity, supported by first-principles calculations showing tunable band gaps.

Findings

Ti substitution induces a large band gap at the Fermi level.

At 75% Ti substitution, the material becomes a half-metallic ferromagnet.

The t2g - eg gap can be tuned by adjusting Ti concentration.

Abstract

We investigate the growth of half metallic phase in a ferromagnetic material using state-of-the-art full potential linearized augmented plane wave method. To address the issue, we have substituted Ti at the Ru-sites in SrRuO3, where SrRuO3 is a ferromagnetic material. Calculated results establish Ti4+ valence states (similar to SrTiO3), which was predicted experimentally. Thus, Ti substitution dilutes the Ru-O-Ru connectivity, which is manifested in the calculated results in the form of significant band narrowing leading to finite gap between t2g and eg bands. At 75% substitution, a large gap (> 2 eV) appears at the Fermi level, e_F in the up spin density of states, while the down spin states contributes at e_F characterizing the system a half-metallic ferromagnet. The t2g - eg gap can be tailored judiciously by tuning Ti concentrations to minimize thermal effects, which is often the major bottleneck to achieve high spin polarization at elevated temperatures in other materials. This study, thus, provides a novel but simple way to fabricate half-metallicity in ferromagnetic materials, which are potential candidates for spin-based technology.