First-principles characterization of ferromagneticMn5Ge3for spintronic applications

Abstract

In the active search for potentially promising candidates for spintronic applications, we focus on the intermetallic ferromagnetic Mn5Ge3 compound and perform accurate first-principles FLAPW calculations within density functional theory. Through a careful investigation of the bulk electronic and magnetic structure, our results for the total magnetization, atomic magnetic moments, metallic conducting character and hyperfine fields are found to be in good agreement with experiments, and are elucidated in terms of a hybridization mechanism and exchange interaction. In order to assess the potential of this compound for spin-injection purposes, we calculate Fermi velocities and degree of spin-polarization; our results predict a rather high spin-injection efficiency in the diffusive regime along the hexagonal c-axis. Magneto-optical properties, such as L2,3 X-ray magnetic circular dichroism, are also reported and await comparison with experimental data.

Magnetic anisotropy in epitaxial Mn5Ge3films

“…This value is very close to the bulk quoted value of 1070 emu/cm 3 obtained experimentally 20 and theoretically. 11 The extrapolation of the linear fit to zero magnetization gives a non-null thickness, which points to the presence of a ferromagnetically dead layer (FDL) of about 1.7 ± 0.3 nm, thus reducing the active magnetic volume. In the following part, the thicknesses used for the magnetization calculations (Figs.…”

“…8 Furthermore, its Curie temperature (296 K) can greatly be enhanced by carbon addition 9 and the resulting materials were shown to display remarkable thermal stability. 10 Finally, its high spin polarization 11 has potential for spin-based devices. During the last decades, the physical properties of this compound have been largely investigated.…”

Simulation of the enhanced Curie temperature in Mn5Ge3Cx compounds

“…2͒ is metallic, in agreement with the recent calculations. 1 The partial DOS of Mn atoms is dominated by the 3d-states, while the largest contribution to Ge DOS is due to 4p-and 4s-states. The DOS at the Fermi level ͑E F ͒ is dominated by the Mn d-states, pointing at the significant Mn-Mn interaction.…”

“…Among them, Mn 5 Ge 3 seems to be a promising candidate due to its compatibility with mainstream silicon technology. 1 The low Curie temperature ͓T C = 304 K ͑Ref. 2͔͒ of this compound, which is a main disadvantage for technological applications, has recently been overcome by carbon doping in Mn 5 Ge 3 C x films.…”

“…Simulation of the enhanced Curie temperature in Mn 5 Ge 3 C x compounds I. Slipukhina, 1 E. Arras, 1 Ph. Mavropoulos, 2 5 Ge 3 C x films with x Ն 0.5 were experimentally shown to exhibit a strongly enhanced Curie temperature T C compared to Mn 5 Ge 3 .…”