Structure, half-metallic and magnetic properties of bulk and (001) surface of Rb2XMoO6 (X = Cr, Sc) double perovskites: a DFT + U study. (1st January 2023)

• Record Type: Journal Article
• Authors: Mebed, Abdelazim M; Mushtaq, Muhammad; Muhammad, Iltaf; Lone, Ikram Un Nabi; AL-Qaisi, Samah; Algethami, Norah; EL-Shamy, E F; Laref, Amel; AL-Hosiny, N M
• Is Part Of: Physica scripta. Volume 98:Number 1(2023)
• Publication Date: 2023-01-01
• Subjects: double perovskites -- magnetic moment -- (001) surface -- density functional theory -- half-metal; Physics -- Periodicals; 530.05
• DOI: 10.1088/1402-4896/aca56b
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Half-metallic (HM) ferromagnets (HM-FMs) with large HM gap and high Curie temperature (TC ) have a great importance in the field of spintronics. In this study, the geometric features, electronic structure and magnetism of two new double perovskites (DPs) represented by Rb2 XMoO6 (X = Cr, Sc) were explored in bulk phase and (001) surface using quantum mechanical total energy calculations based on density functional theory (DFT). The results showed that optimized lattice constant a is 7.96 Å and 8.26 Å for Rb2 CrMoO6 (RCMO) and Rb2 ScMoO6 (RSMO), respectively, in the cubic phase (space group Fm-3m, #225). The cohesive energy Ecoh, formation energy Efor and elastic constants (mechanical) calculations proved that present materials are stable. The magnetic properties were explored in terms of ground state magnetic coupling, total magnetic moment (M) and atomic magnetic moment (m), exchange energy (J), and Curie temperature. It was found that both materials have ferromagnetic coupling in the ground state, with M of integer value of 8.0 μ B (4.0 μ B ), J value of 47 meV(72 meV) and TC of 365 K (557 K) in Rb2 CrMoO6 (Rb2 ScMoO6 ). The electronic properties computed with electronic band structure and density of states demonstrated both DPs to be half-metal with HM gap of 1.61 eV (2.1 eV) in Rb2 Cr-based (Rb2 Sc-based) system. Finally the electronic and magnetic properties of (001) surfaces were investigated and compared with that of bulk phase. Interestingly, bulk HM property was retained in RSMO, but disappeared in RCMO due the emergence of defect states at Fermi level (EF ). The reported results suggest that Rb-based DPs carry some fascinating properties for spin-based devices.