Dopant segregation and giant magnetoresistance in manganese-doped germanium

Direct structural evidences of Mn11Ge8 and Mn5Ge2 clusters in Ge0.96Mn0.04 thin films

“…It has been reported that inhomogeneous Mn distributed in Ge films tends to form Mn-rich magnetic precipitates, [6][7][8] such as Mn 5 Ge 3 and Mn 11 Ge 8 . 10 Jamet et al 11 and Li et al 9 found nanosized Mn-rich GeMn columns in the GeMn films grown on Ge. Bihler et al 6 and Passacantando et al 8 reported Mn 5 Ge 3 clusters in the epitaxially grown GeMn films and the ion implanted GeMn alloys.…”

“…1,2 In particular, Ge x Mn 1−x DMS has attracted considerable attention. [2][3][4][5][6][7][8][9] Many attempts have been devoted to obtaining a room-temperature ferromagnetic Ge x Mn 1−x DMS with high concentration and uniformly distributed Mn. [3][4][5][6][7][8][9] However, the fact of the low solubility of Mn in Ge makes it a challenge task to secure a high Curie temperature DMS.…”

Diluted manganese on the bond-centered site in germanium

“…Ottaviano et al 7 explicitly indicated that, within the detection limit, no Mn atoms were found on the tetrahedral interstitial ͑T͒ site. Li et al 9 used Rutherford backscattering spectrometry in channeling geometry on low temperature MBE ͑LT-MBE͒ grown Mn x Ge 1−x , which resulted in the observation of 24% of the Mn atoms on the S site and 12% on the T site, with the remainder ͑64%͒ distributed randomly throughout the crystal. It is important to note that this lattice location study was hindered by the presence of Mn-rich nanocolumns.…”

Mn behavior in Ge0.96Mn0.04 magnetic thin films grown on Si

“…[2][3][4][5][6][7][8][9][10] One of the key issues to achieve GeMn DMS is to uniformly dope Mn into the Ge matrix. 7,10 It has been reported that the Mn dilution in Ge depends strongly upon the substrate temperature and that inhomogeneous Mn distributed in the Ge films tends to the formation of Mn-rich precipitates, such as Mn 5 Ge 3 4-6 and Mn 11 Ge 8 8,9 phases, which makes it complicated to understand the origin of ferromagnetism of GeMn DMS films. Most of the previous studies have been focused on the structural and magnetic properties of these Mn-rich clusters in GeMn films grown on Ge substrates.…”