@article{fc74c558e9a4456782402f8c80b259b5,
title = "The molecular beam epitaxy growth, structure, and magnetism of Si 1-xMnx films",
abstract = "The type-IV diluted magnetic semiconductor (DMS) [Si (20 {\AA}) Mn (x)] 30 multilayers (MLs) with nominal thickness x=1, 1.5, and 2.0 {\AA} have been prepared by molecular beam epitaxy. The structure, magnetism, and electrical property of these MLs were investigated. Above room temperature ferromagnetism has been observed and structure probed by x-ray absorption spectroscopy. The Mn local structure is similar to Si simulation and the Mn chemical valences of the MLs are in the range from zero (Mn foil) to Mn+2. The relative carrier concentration is sensitive to the formation of room temperature ferromagnetism, suggesting that hole mediated mechanism play an important role in Si:Mn DMSs.",
author = "Chiu, {S. H.} and Hsu, {H. S.} and Huang, {J. C.A.}",
note = "Funding Information: This work has been supported by the National Science Council of the Republic of China under Grant No. NSC 96-2120-M-006-001. FIG. 1. Magnetization of the multilayers [ Si ( 20 {\AA} ) ∕ Mn ( x ) ] 30 as a function of applied field at 300 K for x = 1 (circle), x = 1.5 (diamond), and x = 2.0 (triangle). FIG. 2. Magnetization of the multilayers [ Si ( 20 {\AA} ) ∕ Mn ( x ) ] 30 , (a) x = 1 , (c) x = 1.5 , and (d) x = 2.0 {\AA} , as a function of temperature at an applied field of 50 Oe for zero field cooling (solid symbols) and field cooling (open symbols). (b) shows the fitting results (dashed curve) of the field-cooled data at an applied field of 1000 Oe . FIG. 3. Normalized absorption spectra of the multilayers [ Si ( 20 {\AA} ) ∕ Mn ( x ) ] 30 , x = 1 , 1.5, and 2 {\AA} , at Mn K edge. The spectra of MnO and Mn foils are also provided for reference. Inset presents Fourier transform amplitude of EXAFS at the Mn K edge of the multilayers [ Si ( 20 {\AA} ) ∕ Mn ( x ) ] 30 , x = 1 , 1.5, and 2.0 {\AA} , together with Si K edge simulated by FEFF code, and MnO and Mn metal for reference. FIG. 4. The M s ( 300 K ) ∕ M s ( 6 K ) ratio for [ Si ( 20 {\AA} ) ∕ Mn ( x ) ] 30 with x = 1 , 1.5, and 2.0 {\AA} as a function of relative carrier concentration n c ∕ n i , the trend is guided for eyes. Inset displays room temperature of the Hall effect pareameters as a function of Mn content of the [ Si ( 20 {\AA} ) ∕ Mn ( x ) ] 30 , x = 1 , 1.5, and 2.0 {\AA} MLs. ",
year = "2008",
doi = "10.1063/1.2830974",
language = "English",
volume = "103",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "7",
}