Enhanced magnetic and electrical properties in amorphous Ge:Mn thin films by non-magnetic codoping

Journal Article · Wed Feb 01 00:00:00 EST 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3679076· OSTI ID:22036810

Wenjing, Yin; Kell, Copeland D; Duska, Chris; Jiwei, Lu; Floro, Jerrold A ^[1]; Li, He; Hull, Robert ^[2]; Dolph, Melissa C ^[3]; Wolf, Stuart A ^[1]

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1. Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)
2. Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
3. Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States)

Amorphous Ge{sub 1-x}Mn{sub x} thin films have been prepared by co-depositing Ge and Mn on SiO{sub 2}/Si using an ultrahigh vacuum molecular beam epitaxy system. Across a range of growth temperatures and Mn concentrations (2.8 at. %, 10.9 at. %, and 21.3 at. %), we achieved enhanced magnetic and electrical properties with non-magnetic codopants dispersed in the films. Self-assembled Mn-rich amorphous nanostructures were observed in the amorphous Ge matrix, either as isolated nanoclusters or as nanocolumns, depending on Mn concentration. The ferromagnetic saturation moments were found to increase with Mn concentration and reached a maximum of 0.7 {mu}{sub B}/Mn in the as-grown samples. Two magnetic transition temperatures around 15 K and 200 K were observed in these amorphous MBE-grown samples. Coercivity is considered within the context of local magnetic anisotropy. The anomalous Hall effect confirmed a strong correlation between the magnetization and transport properties, indicating that global ferromagnetic coupling was carrier-mediated rather than through direct exchange. In addition, negative magnetoresistance was detected from 5 K to room temperature.

• OSTI ID: 22036810
• Journal Information: Journal of Applied Physics, Vol. 111, Issue 3; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ANISOTROPY
COERCIVE FORCE
COUPLING
FERROMAGNETIC MATERIALS
GERMANIUM
HALL EFFECT
LAYERS
MAGNETIC MOMENTS
MAGNETIZATION
MAGNETORESISTANCE
MANGANESE
MATRIX MATERIALS
MOLECULAR BEAM EPITAXY
NANOSTRUCTURES
SEMICONDUCTOR MATERIALS
SILICON OXIDES
THIN FILMS
TRANSITION TEMPERATURE