Structural, magnetic, and magneto-optical properties of Ni/Rh(001) ultrathin films: theoretical study

Abstract

Ultrathin films exhibit unique properties due to strong interfacial effects, making them highly promising for a wide range of technological applications. This study presents a comprehensive theoretical investigation of Ni n /Rh(001) ultrathin films, grown by pseudomorphic epitaxy, using density functional theory within a spin-polarized relativistic framework (spin-polarized relativistic linear muffin-tin orbitals and atomic sphere approximation). Our calculations reveal that the nickel layers adopt a body-centered tetragonal structure on the rhodium substrate in the [001] direction, characterized by a tetragonality ratio of c/ a = 1.18, which significantly affects the magnetic and structural properties of the system. We found that Ni layers exhibit increased magnetic moments compared to bulk Ni, with intra- and inter-plane ferromagnetic coupling. Additionally, the rhodium last layer shows an induced magnetic moment due to hybridization with nickel atoms, with significant variations across layers. Furthermore, we analyzed the polar magneto-optical Kerr effect spectra, identifying specific interband transitions responsible for the observed Kerr rotations. These results provide critical insights into the correlation between structure, magnetism, and magneto-optical properties in ultrathin films, demonstrating their potential for applications in data storage, spintronic, and biosensing technologies.