Dependence of magnetic properties on the growth temperature of Mn0.04Ge0.96 grown on Si (001)

Magnetic properties of Mn doped crystalline and amorphous Ge thin films grown on Si (111)

“…A single FMR peak with a small uniaxial anisotropy with the hard axis perpendicular to film surface is observed. This indicates that the FMR resonance field is dominated by the magnetic shape anisotropy field since the sample is a thin film, consistent with the previous works on Mn 5 Ge 3 thin films [28,29]. Figure 7b shows the temperature dependence of the FMR spectra with the magnetic field applied in the in-plane direction.…”

“…The majority of Mn doped Ge films reported to date contain different magnetic phases and precipitates depending on the distribution of Mn atoms in Ge, which is mainly governed by Mn diffusion mechanism during growth procedure [6,7]. Ion implantation and low temperature synthesis techniques with very low doping concentration are highly desirable to minimize precipitate formation, but the main disadvantage of these growth processes is the large number of defects that are introduced during growth [8][9][10][11]. Since the defects produce local lattice distortions, the position of Mn atoms around the defects is different from their crystallographic equilibrium positions.…”

Role of nitrogen on the magnetic properties of MBE grown Mn0.04Ge0.96 films

“…This indicates a ferromagnetic transition at about 300 K and an additional anomaly at a lower temperature. We have observed similar magnetization results on Mn doped Ge samples grown at high temperature and interpreted the results based on the presence of two different ferromagnetic structures in the sample, namely, Mn þ 2 ions containing Mn rich regions, and Mn 3 Ge 5 nanoparticles with T c ¼296 [11]. We synthesized the films as sequential multilayer deposition, where Mn atoms were first sited on germanium layer and further diffused within above Ge over layer depending on substrate temperature.…”

“…Later, a thin Ge buffer layer was grown on atomically clean surface at 450°C. To overcome low Mn solubility in Ge, we tried to limit the diffusion of Mn atoms in Ge by using sequential multilayer deposition [11]. Both films were grown at 130°C substrate temperature with the same Mn cell temperature.…”

“…To control the Mn distribution and enhance the possibility of introducing substitutional dopants, several growth parameters have been varied during the synthesis of Mn doped Ge such as growth temperature, Mn concentration and film thickness [6][7][8][9][10]. Recently, we have shown that the number of active Mn atoms in Ge can be promoted at relatively low temperatures without forming secondary phases, if sequential multilayer deposition of Mn and Ge stacks is carried out [11]. According to first-principles calculations, another way to obtain Mn x Ge 1 À x with enhanced T c and a magnetic moment is introducing a secondary n-type dopant [12,13].…”