Effect of Oxygen on the Quantum, Magnetic, and Thermodynamic Properties of Co Nanowires on the Reconstructed Anisotropic
- PDF / 920,340 Bytes
- 10 Pages / 612 x 792 pts (letter) Page_size
- 7 Downloads / 163 Views
MOLECULES, OPTICS
Effect of Oxygen on the Quantum, Magnetic, and Thermodynamic Properties of Co Nanowires on the Reconstructed Anisotropic (1 × 2)/Au(110) and (1 × 2)/Pt(110) Surfaces: Ab Initio Approach Ya. S. Kosheleva,b,* and D. I. Bazhanova,c,d a Moscow
b
State University, Moscow, 119991 Russia Skolkovo Institute of Science and Technology, Innovative Center Skolkovo, Moscow, 121205 Russia c Dorodnicyn Computing Centre, Russian Academy of Sciences, Moscow, 119333 Russia d Moscow Aviation Institute, Moscow, 125993 Russia *e-mail: [email protected] Received May 10, 2017; in final form, April 13, 2018
Abstract—Ab initio theoretical study of the quantum magnetic properties of Co nanowires on the pure and oxygen-reconstructed (1 × 2)/Au(110) and (1 × 2)/Pt(110) surfaces is performed. Their structures and electronic configurations are calculated using the electron density functional theory. High values of magnetic moment and magnetic anisotropy energies of Co atoms are found on both pure and oxygen-reconstructed (1 × 2)/Au(110) and (1 × 2)/Pt(110) surfaces. The adsorption of oxygen atoms on the (1 × 2)/Au(110) substrate is shown to affect the structural arrangement of Co nanowire atoms on this substrate and to increase the magnetic anisotropy energy (by 1.91 meV per nanowire atom). The adsorption of oxygen on the Pt(110) substrate substantially decreases the magnetic anisotropy energy of the Co nanowire on it (by 5.98 meV per atom). The origin of these changes is revealed by analyzing the local densities of states of the d electrons of nanowire atoms. The temperature ranges of the states with the lowest free surface energy are determined using the atomistic thermodynamics methods. These data and the available experimental data are used to predict the possibility of observing the structures under study in experiments. DOI: 10.1134/S1063776118080204
1. INTRODUCTION The systems that are capable of retaining strong magnetization in external magnetic fields in the presence of electric currents and thermal fluctuations as well as the systems having a high magnetic anisotropy energy (MAE) are the most suitable structures for magnetic storage devices. A strong magnetic anisotropy, i.e., a strong dependence of the magnetic properties on a magnetization direction, cannot be observed in high-symmetry structures; therefore, systems with a structural anisotropy are the most suitable objects for investigations. For this reason, low-dimensional systems, such as nanofilms, nanowires, and atomic chains, are of particular interest due to their distinct spatial direction. To form structures with a high MAE, a strong spin–orbit coupling should be combined with a high magnetic moment. A strong spin–orbit coupling is known to be characteristic of noble metals, such as Au, Pt, and Pd [1]. Such metals are used as substrates for the growth of magnetic anisotropic structures. For such kind of structures, 3d metal nanowires are of par-
ticular interest for investigations, and the systems constructed from them are promising objects
Data Loading...
