Magnetic characteristics of epitaxial Ge(Mn,Fe) diluted films —a new room temperature magnetic semiconductor?

Chemical and magnetic profile of magnetic semiconductors as probed by polarized neutron reflectivity

“…The magnetization that was observed for DMS4Fe2Mn from SQUID, is therefore cannot be intrinsic to the DMS layer but, can be owed to the presence of segregated clusters. Our present results for DMS2Fe4Mn corroborate with previous measurements by TEM or SQUID on similar specimens 5,6 . This is further confirmed with the TREFF data as we find that for DMS2Fe4Mn, a clear improvement (improved by ∼0.05) is achieved when M 2 is employed as compared to M 1 .…”

“…5,6 TEM indeed showed the formation of precipitates depending upon the content of magnetic species 5 for the two compositions. A 50 nm of cap-layer (ZnS) on top imposes a serious limitation in extracting the changes in non-magnetic SLD profiles by x-ray after the samples are annealed 6 .…”

“…5 For an annealing temperature T A = 300 C a homogeneous alloy is observed by XRR measurements. 6 Magnetization measurements by a superconducting quantum interference device (SQUID) and magnetotransport measurements reveal ferromagnetic ordering, but show two different T C s at 205 K and above 300 K for "DMS2Fe4Mn", which we relate to two magnetic phases.…”

Surface characterization ofMnxGe1−xandCryGambardella1, Claude2, Rusponi3 et al. 2007Phys. Rev. B361270View full textAdd to dashboardCite

“…4,5 Although most activity is focused on group III-Mn-V materials, there is steadily increasing interest in Ge-based DMS, driven by their potential integration in standard Si semiconductor technology. 2,[6][7][8][9][10][11][12][13] Several growth techniques have been employed to produce MnGe compounds, including low-temperature molecular beam epitaxy ͑MBE͒, 2,6-9 furnace melting, 14,15 and implantation of high-energy Mn 2+ ions into single crystal Ge wafers. [16][17][18] The investigation of the magnetic properties of MnGe compounds, however, reveals very significant differences depending on the growth method.…”

Group-IV-diluted magnetic semiconductor FexSi1−x thin films grown by molecular beam epitaxy

“…Fe x Ge 1Àx (xo0.4) amorphous alloy thin films which are fabricated by thermal co-evaporation show a room temperature T c [7]. By using a layer-by-layer deposition scheme at an elevated temperature Ge 1À(x+y) (Mn x , Fe y ) DMS thin films with Mn and Fe concentrations of several percent have been expitaxially grown on GaAs substrate, and they exhibit a Curie temperature even up to 350 K [8,9]. Compared with Ge-based DMS materials, Si-based DMS materials are less studied and usually Mn is used as a magnetic dopant.…”