An unusual phenomenon of surface reaction observed during Ge overgrowth on Mn₅Ge₃/Ge(111) heterostructures

Effect of carbon on structural and magnetic properties of $$\hbox {Ge}_{1-x}\hbox {Mn}_{x}$$ nanocolumns

“…Furthermore, the spinodal decomposition, which is also involved in the columnar phase separation [1,7], has been substantially weakened since carbon might act as energy barrier centres during the growth of the layers. A robust argument supports this finding, may be found in a comparable structure, where only few monolayers of carbon deposited on top of the Mn 5 Ge 3 greatly suppress the Mn diffusion into the adjacent Ge layer [19]. We note that we have carried out further experiments, in which we have added the same amount of carbon throughout the homoepitaxial growth of Ge on Ge substrates.…”

“…Curie temperature of about 300 K is observed after annealing at 450 and 650°C. It is worth noting that the shape of the M(T ) curves obtained after annealing is very similar to that of the Mn 5 Ge 3 compound [18][19][20]. Thus, carbon doping in this case does not allow to improve the thermal stability of the films.…”

“…Post-annealing was carried out from 450 to 650°C in high vacuum and the annealing duration was 20 min to insure a complete phase transformation. The carbon concentration was estimated from the change of Si(001) surface reconstructions from (2×1) to c(4×4) upon adsorption of a carbon sub-monolayer [10][11][12][13][14][15][16][17][18][19][20][21].…”

Thiol-functionalization of Mn 5 Ge 3 thin films

“…[37][38][39]. In addition, it is known that under vacuum conditions, the surface of Mn 5 Ge 3 is terminated by Mn atoms therefore the SFE value of an unchanged surface might be close to that of the Mn metal, around 1350-1600 mJ.m -2 [40,41]. Moreover, the reported SFE value for a pure manganese oxide surface (Mn 3 O 4 , 72 mJ.m -2 ) supports the XPS data, evidencing that the surface of a Mn 5 Ge 3 thin film is strongly affected both by air exposition and solvents treatments [42].…”

Epitaxial Growth of High Curie-Temperature Ge1-xMnx quantum dots on Si(001) by auto-assembly

“…To get spin injectors of higher Curie temperatures, alternative approaches, such as the use of epitaxial high-T C Mn 5 Ge 3 and carbon-doped Mn 5 Ge 3 C x compounds, have been developed [19][20][21][22][23][24][25][26][27]. However, since these compounds are intermetallic, they form a Schottky barrier at the interface with Ge, which may limit the efficiency of spin injection.…”