Theoretical study of the magnetic properties of (Fe,Co) monolayers coupled by Ir (001) spacer

Abstract

The study of magnetic materials has widely grown in importance due to its large applications such as spintronic devices. Ultrathin films of transition metals (TMs) – deposited on various metallic substrates offer a versatile laboratory to study itinerant magnetism in two dimensions. These materials have been studied extensively depending on the magnetic atoms compositions (typically 3d metals), the choice of the substrate, and the substrate orientation. We used the density functional theory (DFT) technique to predict different magnetic structures of materials such as magnetic domain wall and skyrmions. Indeed, this technique is powerful to explore the magnetic properties of these systems. In the present work, we used the Full-Potential Linearised Augmented Plane-Wave method (FP-LAPW), which was implemented in the FLEUR code to investigate the magnetic properties of the 3d transition alloys (Fe1-XCoX) monolayers separated by the Ir(001) substrate. The parameterization GGA for the exchange and correlation potential was used. By including relaxations in all calculations, the obtained results show that Fe monolayer promotes antiferromagnetic (AFM) state (-89 meV/Fe atoms) with a magnetic moment value of 2.83ìB. Additionally, ferromagnetic (FM) ground states were determined for both FeCo (45.4 meV/Fe atoms) and Co (119 meV/Co atoms). The size of the local magnetic moments were figured out as follows FeCo (Fe: 2.98ìB , Co:1.73ìB) and Co 1.85ìB. The magnetic anisotropy energies of these ultrathin magnetic films were investigated in their magnetic ground states. The easy axis of the magnetization was predicted to be in the film plane for Fe and FeCo monolayer. The interlayer exchange coupling with respect to the trends of the magnetic order of 3d monolayers on Ir (001) substrate was analyzed. The dependence of the strength of IEC on the Ir layer thickness has been observed with an oscillation period of 4 layers between FM and AFM couplin