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1.
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Sensitivity of 57Fe emission Mössbauer spectroscopy to Ar and C induced defects in ZnO
/ Bharuth-Ram, K (DUT, Durban) ; Mølholt, T E (CERN) ; Langouche, G (Leuven U.) ; Geburt, S (U. Jena (main)) ; Ronning, C (U. Jena (main)) ; Doyle, T B (iThemba LABS ; KwaZulu Natal U.) ; Gunnlaugsson, H P (CERN) ; Johnston, K (CERN) ; Mantovan, R (IMM-CNR, Brianza) ; Masenda, H (Witwatersrand U.) et al.
/Isolde
Emission Mössbauer Spectroscopy (eMS) measurements, following low fluence (<1012 cm−2) implantation of 57Mn (t 1/2 = 1.5 min.) into ZnO single crystals pre-implanted with Ar and C ions, has been utilized to test the sensitivity of the 57Fe eMS technique to the different types of defects generated by the different ion species. The dominant feature of the Mössbauer spectrum of the Ar implanted ZnO sample was a magnetic hyperfine field distribution component, attributed to paramagnetic Fe3+, while that of the C implanted sample was a doublet attributed to substitutional Fe2+ forming a complex with the C dopant ions in the 2− state at O vacancies. [...]
2016
- Published in : Hyperfine Interact. 237 (2016) 81
External link: Link to fulltext on ICAME2015 document server
In : International Conference on the Applications of the Mössbauer Effect, Hamburg, Germany, 13 - 18 Sep 2015, pp.81
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2.
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Atomic-scale study of the amorphous-to-crystalline phase transition mechanism in GeTe thin films
/ IS578 Collaboration
The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of 57Fe emission Mössbauer spectroscopy, following dilute implantation of 57Mn (T½ = 1.5 min) at ISOLDE/CERN, to study the electronic charge distribution in the immediate vicinity of the 57Fe probe substituting Ge (FeGe), and to interrogate the local environment of FeGe over the amorphous-crystalline phase transition in GeTe thin films. Our results show that the local structure of as-sputtered amorphous GeTe is a combination of tetrahedral and defect-octahedral sites. [...]
2017
- Published in : Sci.Rep. 7 (2017) 8234
Fulltext: PDF;
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3.
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Atomic-Scale Magnetic Properties of Truly 3d-Diluted ZnO
/ Mantovan, Roberto (IMM-CNR, Agrate Brianza,Italy) ; Gunnlaugsson, Haraldur Páll (Leuven U. ; Aarhus U.) ; Johnston, Karl (CERN) ; Masenda, Hilary (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Mølholt, Torben Esmann (Iceland U.) ; Naidoo, Deena (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Ncube, Mehluli (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Shayestehaminzadeh, Seyedmohammad (Iceland U.) ; Bharuth-Ram, Krish (DUT, Durban ; iThemba LABS) ; Fanciulli, Marco (IMM-CNR, Agrate Brianza,Italy ; Milan Bicocca U.) et al.
In search for dilute magnetic semiconductors, the magnetic properties at the atomic-scale of Fe atoms incorporated in ZnO, in a concentration range of more than five orders of magnitude from 1×10−5 to 2.2 at% have been probed using emission 57 Fe Mössbauer spectroscopy on implanted 57Mn and 57Co produced at ISOLDE/CERN. In the ultra-dilute regime (10−5 at%), the system shows isolated paramagnetic Fe3+ ions with a spin–lattice type of relaxation. [...]
2015
- Published in : Advanced Electronic Materials 1 (2015) 1400039
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4.
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Lattice sites, charge states and spin–lattice relaxation of Fe ions in 57Mn+ implanted GaN and AlN
/ Masenda, H (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Naidoo, D (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Bharuth-Ram, K (DUT, Durban ; iThemba LABS) ; Gunnlaugsson, H P (CERN ; KU Leuven, Dept. Phys. Astron.) ; Johnston, K (CERN) ; Mantovan, R (CNR-IMM Agrate Brianza, Italy) ; Mølholt, T E (CERN) ; Ncube, M (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Shayestehaminzadeh, S (RWTH Aachen U.) ; Gíslason, H P (Iceland U.) et al.
The lattice sites, valence states, resulting magnetic behaviour and spin–lattice relaxation of Fe ions in GaN and AlN were investigated by emission Mössbauer spectroscopy following the implantation of radioactive 57Mn+ ions at ISOLDE/CERN. Angle dependent measurements performed at room temperature on the 14.4 keV γ-rays from the 57Fe Mössbauer state (populated from the 57Mn β− decay) reveal that the majority of the Fe ions are in the 2+ valence state nearly substituting the Ga and Al cations, and/or associated with vacancy type defects. [...]
2016 - 9 p.
- Published in : J. Magn. Magn. Mater. 401 (2016) 1130-1138
Fulltext: PDF;
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5.
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Interstitial Fe in MgO
/ Mølholt, T E (Iceland U.) ; Mantovan, R (IMM, Bologna) ; Gunnlaugsson, H P (Aarhus U.) ; Svane, A (Aarhus U.) ; Masenda, H (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Naidoo, D (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Bharuth-Ram, K (Durban-Westville U.) ; Fanciulli, M (IMM, Bologna ; Milan Bicocca U.) ; Gislason, H P (Iceland U.) ; Johnston, K (CERN) et al.
Isolated Fe-57 atoms were studied in MgO single-crystals by emission Mossbauer spectroscopy following implantation of Mn-57 decaying to Fe-57. Four Mossbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. [...]
2014
- Published in : J. Appl. Phys. 115 (2014) 023508
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6.
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Defect annealing in Mn/Fe-implanted TiO2(rutile)
/ Gunnlaugsson, H P (Aarhus U.) ; Mantovan, R (IMM, Bologna) ; Masenda, H (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Mølholt, T E (Iceland U.) ; Johnston, K (CERN) ; Bharuth-Ram, K (Durban-Westville U.) ; Gislason, H (Iceland U.) ; Langouche, G (Leuven U.) ; Naidoo, D (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Ólafsson, S (Iceland U.) et al.
A study of the annealing processes and charge state of dilute Fe in rutile TiO2 single crystals was performed in the temperature range 143-662 K, utilizing online 57Fe emission Mossbauer spectroscopy following low concentrations (< 10(-3) at\%) implantation of 57Mn (T-1/2 = 1.5 min). Both Fe3+ and Fe2+ were detected throughout the temperature range. [...]
2014
- Published in : J. Phys. D 47 (2014) 065501
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7.
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Emission Mössbauer spectroscopy of advanced materials for opto- and nano- electronics
/ Gunnlaugsson, HP (Department of Physics and Astronomy, Aarhus University, DK-8000 Århus C, Denmark) ; Ólafsson, S (Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavík, Iceland) ; Bharuth-Ram, K (iThemba LABS, P.O. Box 722, Somerset West 7129, South Africa) ; Correia, JG (Departamento Física, Instituto Tecnológico e Nuclear, Sacavém, Portugal) ; Gíslason, HP (Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavík, Iceland) ; Johnston, K (EP Division, CERN, CH-1211 Geneva 23, Switzerland) ; Langouche, G (Instituut voor Kern-en Stralings fysika, University of Leuven, B-3001 Leuven, Belgium) ; Madsen, MB (Niels Bohr Institute, Universtity of Copenhagen, DK-2100 Copenhagen Oe, Denmark) ; Mantovan, R (CNR-IMM MDM Laboratory, Via C. Olivetti 2, 20041 Agrate Brianza (MB), Italy) ; Masenda, H (School of Physics, University of the Witwatersrand, WITS 2050, South Africa) et al.
CERN-INTC-2012-005 ; INTC-P-275-ADD-1.
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2012.
Fulltext - Original Document (INTC-P-275)
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8.
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Paramagnetism in Mn/Fe implanted ZnO
/ Gunnlaugsson, HP (Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark.) ; Fanciulli, M (CNR IMM MDM Lab, I-20041 Agrate Brianza, MB, Italy. ; Univ Milano Bicocca, Dept Mat Sci, I-20125 Milan, Italy.) ; Weyer, G (Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark.) ; Kobayashi, Y (RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan.) ; Bharuth-Ram, K (Univ KwaZulu Natal, Sch Phys, ZA-4001 Durban, South Africa. ; iThemba Labs, ZA-7129 Somerset W, South Africa.) ; Olafsson, S (Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland.) ; Gislason, H P (Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland.) ; Gunnlaugsson, H P (Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark.) ; Yoshida, Y (Shizuoka Inst Sci & Technol, Shizuoka 4378555, Japan.) ; Langouche, G (Univ Louvain, Inst Kern En Stralings Fys, B-3001 Louvain, Belgium.) et al.
Prompted by the generally poor understanding of the nature of magnetic phenomena in 3d-metal doped ZnO, we have undertaken on-line Fe-57 Mossbauer spectroscopy on ZnO single crystals in an external magnetic field of 0.6 T, following the implantation of radioactive Mn-57 ions at room temperature. The Mossbauer spectra of the dilute Fe impurities are dominated by sextets whose angular dependence rules out an ordered magnetic state (which had been previously proposed) but are well accounted for on the basis of Fe3+ paramagnetic centers on substitutional Zn sites with unusually long relaxation times (> 20 ns) [...]
2010
- Published in : Appl. Phys. Lett. 97 (2010) 142501
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9.
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Temperature and dose dependence of defect complex formation with ion implanted Mn/Fe in ZnO
/ Mølholt, T E (Iceland U.) ; Mantovan, R (MDM Observ.) ; Gunnlaugsson, H P (Aarhus U.) ; Bharuth-Ram, K (iThemba LABS) ; Fanciulli, M (MDM Observ. ; Milan Bicocca U.) ; Gíslason, H P (Iceland U.) ; Johnston, K (CERN) ; Kobayashi, Y (Wako, RIKEN) ; Langouche, G (Leuven U.) ; Masenda, H (Witwatersrand U.) et al.
57Fe Mössbauer spectroscopy following ion implantation of radioactive 57Mn+ ( T1/2=85.4 s) has been applied to study the formation of Fe/Mn implantation-induced defects in ZnO at temperatures between 319 and 390 K. The formation of ferric iron–vacancy complexes is found to depend strongly on the implanted dose and to be faster and more efficient at higher temperatures [...]
2009
- Published in : Physica B 404 (2009) 4820-4822
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10.
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Emission Mössbauer spectroscopy of advanced materials for opto- and nano-electronics
/ Gislason, H P et al.
- ISOLDE.
Approved: 03 March 2010.-
Status: Completed on 04 May 2020
Experiment: IS501
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