High-temperature ferromagnetism in laser-deposited layers of silicon and germanium doped with manganese or iron impurities

Mn-doped Ge and Si: A Review of the Experimental Status

“…The films are very conductive with carrier concentrations up to 10 20 cm −3 . As shown in Figure 21 , anomalous Hall effect is observed up to 150 K. In the work of Demidov et al [ 82 ], Mn-doped Si films were prepared on Al 2 O 3 substrates by laser deposition. They observed anomalous Hall effect even up to room temperature.…”

High-temperature diamond-like Si-based ferromagnet with self-organized superlattice distribution of Mn impurity

“…The concentration of holes p ≥ 7.5·10 20 cm -3 means that not less of 10% of Mn impurity atoms is electric active. As well as in [17][18][19] , at room temperature FMR spectra consisted of several peaks of resonant absorption which with decreasing of temperature merge in single rather narrow peak. According to FMR data at 93К, if to consider that manganese spin is equal 5/2, the concentration N Mn =8·10 21 cm -3 practically coincides with xray value 15%Mn (N Mn =7.5·10 21 cm -3 ), i.e.…”

“…The splitting of FMR spectrum on some peaks of absorption with temperature rise (see fig. 1 in 19 ) is caused by presence of block distortions of crystal structure of Si:Mn layer instead of non-uniform distribution of Mn impurity in the DMS as it was supposed 19 . The patterns of SAED along the direction <110> of Si:Mn layer and GaAs substrate are shown on Fig.…”

“…Especially interesting DMS are on basis of elementary silicon semiconductor because of their compatibility with the most widespread silicon technology. Numerous attempts of synthesis ferromagnetic DMS on basis of silicon, doped by 3d -impurities, were undertaken [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] . The problem of synthesis such DMS is even more difficult than in case of III-V compounds because of the close to equilibrium solubility of middle 3d -iron group elements impurities in Si is about 10 16 cm -3 on two order more low, these impurities mainly occupy position of interstitials and show donor properties 23,24 .…”

“…Apparently the film Si:Mn, except for block distortions of crystal structure, is mainly epitaxial with diamondlike structure in which the lattice planes (110) are oriented perpendicularly to border of Si:Mn/GaAs and are parallel to similar (110) planes of GaAs substrate. 18 and introduced by this impurity high hole conductivity of deposited from laser plasma Si:Mn films [17][18][19] . Differing from silicon part of sample chess alternation of dark and light points on the right on fig.2 is obviously caused by raised negative charge on As atoms on comparison with Ga atoms in partially ionic III-V GaAs crystal substrate.…”