1.
|
Annealing studies combined with low temperature emission Mössbauer spectroscopy of short-lived parent isotopes: Determination of local Debye–Waller factors
/ Gunnlaugsson, H P (Iceland U.) ; Masenda, H (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Mølholt, T E (Denmark, Tech. U.) ; Bharuth-Ram, K (KwaZulu Natal U. ; DUT, Durban) ; Ólafsson, S (Iceland U.) ; Johnston, K (CERN) ; Schell, J (CERN ; Duisburg-Essen U.) ; Gislason, H P (Iceland U.) ; Krastev, P B (Sofiya, Inst. Nucl. Res.) ; Mantovan, R (SGS Thomson, Milan) et al.
An extension of the online implantation chamber used for emission Mössbauer Spectroscopy (eMS) at ISOLDE/CERN that allows for quick removal of samples for offline low temperature studies is briefly described. We demonstrate how online eMS data obtained during implantation at temperatures between 300 K and 650 K of short-lived parent isotopes combined with rapid cooling and offline eMS measurements during the decay of the parent isotope can give detailed information on the binding properties of the Mössbauer probe in the lattice. [...]
2021
- Published in : Rev. Sci. Instrum. 92 (2021) 013901
Fulltext: PDF;
|
|
2.
|
Charge states and lattice sites of dilute implanted Sn in ZnO
/ Mølholt, T E (CERN) ; Gunnlaugsson, H P (Leuven U.) ; Johnston, K (CERN) ; Mantovan, R (CNR-IMM Agrate Brianza, Italy) ; Röder, J (CERN ; RWTH Aachen U.) ; Adoons, V (KwaZulu Natal U.) ; Mokhles Gerami, A (CERN ; K.N. Toosi U.) ; Masenda, H (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Matveyev, Y A (Moscow, MIPT) ; Ncube, M (U. Witwatersrand, Johannesburg, Sch. Phys.) et al.
/ISOLDE
The common charge states of Sn are 2+ and 4+. While charge neutrality considerations favour 2+ to be the natural charge state of Sn in ZnO, there are several reports suggesting the 4+ state instead. [...]
2017
- Published in : J. Phys. : Condens. Matter 29 (2017) 155701
|
|
3.
|
Sensitivity of $^{57}$Fe 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
|
|
4.
|
Emission Mössbauer spectroscopy study of fluence dependence of paramagnetic relaxation in Mn/Fe implanted ZnO
/ Masenda, H (Witwatersrand U.) ; Geburt, S (Institute of Solid State PhysicsUniversity of JenaJenaGermany ; Jena U.) ; Bharuth-Ram, K (DUT, Durban ; KwaZulu Natal U.) ; Naidoo, D (Witwatersrand U.) ; Gunnlaugsson, H P (CERN ; Leuven U.) ; Johnston, K (CERN) ; Mantovan, R (IMM-CNR, Brianza) ; Mølholt, T E (CERN) ; Ncube, M (Witwatersrand U.) ; Shayestehaminzadeh, S (RWTH Aachen U.) et al.
/ISOLDE
Emission Mössbauer Spectroscopy following the implantation of radioactive precursor isotope $^{57}$Mn$^{+}$ (T$_{1/2}$= 1.5 min) into ZnO single crystals at ISOLDE/CERN shows that a large fraction of $^{57}$Fe atoms produced in the $^{57}$Mn beta decay is created as paramagnetic Fe$^{3+}$ with relatively long spin-lattice relaxation times. Here we report on ZnO pre-implanted with $^{56}$Fe to fluences of 2×10$^{13}$, 5×10$^{13}$ and 8 × 10$^{13}$ ions/cm2 in order to investigate the dependence of the paramagnetic relaxation rate of Fe$^{3+}$ on fluence. [...]
2016 - 7 p.
- Published in : Hyperfine Interact. 237 (2016) 40
Fulltext: PDF; 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.40
|
|
5.
|
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 $^{57}Mn$ and $^{57}Co$ produced at ISOLDE/CERN. In the ultra-dilute regime ($10 ^{−5}$ at%), the system shows isolated paramagnetic $Fe^{3+}$ ions with a spin–lattice type of relaxation. [...]
2015
- Published in : Advanced Electronic Materials 1 (2015) 1400039
|
|
6.
|
$^{57}$Fe Mössbauer study of epitaxial TiN thin film grown on MgO (1 0 0) by magnetron sputtering
/ Qi, B (Iceland U.) ; Gunnlaugsson, H P (Iceland U.) ; Mokhles Gerami, A (K.N. Toosi U.) ; Gislason, H P (Iceland U.) ; Ólafsson, S (Iceland U.) ; Magnus, F (Iceland U.) ; Mølholt, T E (CERN) ; Masenda, H (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Tarazaga Martín-Lueugo, A (Linz U.) ; Bonanni, A (Linz U.) et al.
/ISOLDE
The properties and performance of TiN thin films are closely related to the concentration and mobility of lattice defects in the thin film structures of TiN. This makes a local atomic scale study of TiN thin films an ever-growing demand. [...]
2019 - 10 p.
- Published in : Appl. Surf. Sci. 464 (2019) 682-691
|
|
7.
|
Metal-insulator transition in crystalline V$_2$O$_3$ thin films probed at atomic-scale using emission Mössbauer spectroscopy
/ Qi, B (Iceland U.) ; Gunnlaugsson, H P (Iceland U.) ; Ólafsson, S (Iceland U.) ; Gislason, H P (Iceland U.) ; Thorsteinsson, E B (Iceland U.) ; Arnalds, U B (Iceland U.) ; Mantovan, R (CNR-IMM, Catania) ; Unzueta l, I (Basque U., Bilbao) ; Zyabkin, D V (Ilmenau Tech. U.) ; Bharuth Ram, K (KwaZulu Natal U. ; DUT, Durban) et al.
Microscopic understanding the metal-to-insulator transition (MIT) in strongly correlated materials is critical to
the design and control of modern “beyond silicon” Mott nanodevices. In this work, the local MIT behaviors in
single crystalline V$_2$O$_3$ thin films were probed on an atomic scale by online $^{57}$Fe emission Mössbauer spectroscopy (eMS) following dilute ($<10^{-3}$ at.%) implantation of $^{57}$Mn$^+$ (T$_{1/2}$ = 90 s). [...]
2020
- Published in : Thin Solid Films 714 (2020) 138389
|
|
8.
|
Temperature Dependence of the Hyperfine Magnetic Field at Fe Sites in Ba-Doped BiFeO$_3$ Thin Films Studied by Emission Mössbauer Spectroscopy
/ Heiniger-Schell, Juliana (CERN ; Duisburg-Essen U.) ; Bharuth-Ram, Krish (ENS, Lyon, Lab. Phys. ; KwaZulu Natal U. ; DUT, Durban) ; Naicker, Kimara (ENS, Lyon, Lab. Phys. ; KwaZulu Natal U.) ; Masondo, Vusumuzi (DUT, Durban) ; Dang, Thien Thanh (Duisburg-Essen U.) ; Escobar, Marianela (Duisburg-Essen U.) ; Díaz-Guerra, Carlos (Madrid U.) ; Marschick, Georg (Vienna, Tech. U.) ; Masenda, Hilary (Witwatersrand U.) ; Gunnlaugsson, Haraldur P (Iceland U.) et al.
Emission $^{57}$Fe Mössbauer spectroscopy (eMS), following the implantation of radioactive $^{57}$Mn+ ions, has been used to study the temperature dependence of the hyperfine magnetic field at Fe sites in Ba-doped BiFeO$_3$ (BFO) thin films. $^{57}$Mn β decays (t$_{1/2}$ = 90 s) to the 14.4 keV Mössbauer state of $^{57}$Fe, thus allowing online eMS measurements at a selection of sample temperatures during Mn implantation. [...]
2023 - 13 p.
- Published in : Crystals 13 (2023) 724
Fulltext: PDF;
|
|
9.
|
Unusual charge states and lattice sites of Fe in Al$_{x}$Ga$_{1−x}$N:Mn
/ Masenda, Hilary (Witwatersrand U. ; Philipps U. Marburg) ; Gunnlaugsson, Haraldur Páll (Iceland U.) ; Adhikari, Rajdeep (Linz U.) ; Bharuth-Ram, Krish (DUT, Durban) ; Naidoo, Deena (Witwatersrand U.) ; Tarazaga Martín-Luengo, Aitana (Linz U.) ; Unzueta, Iraultza (Basque U., Bilbao) ; Mantovan, Roberto (CNR-IMM, Catania) ; Mølholt, Torben Esmann (CERN) ; Johnston, Karl (CERN) et al.
Charge states and lattice sites of Fe ions in virgin and Mn-doped Al$_{x}$Ga$_{1−x}$N samples were investigated using $^{57}$Fe emission Mössbauer spectroscopy following radioactive $^{57}$Mn$^{+}$ ion implantation at ISOLDE, CERN. In the undoped Al$_{x}$Ga$_{1−x}$N, Fe$^{2+}$ on Al/Ga sites associated with nitrogen vacancies and Fe$^{3+}$ on substitutional Al/Ga sites are identified. [...]
2022 - 12 p.
- Published in : New J. Phys. 24 (2022) 103007
Fulltext: PDF;
|
|
10.
|
Compositional Dependence of Epitaxial
L
1
0
‐Mn
x
Ga Magnetic Properties as Probed by
57
Mn/Fe and
119
In/Sn Emission Mössbauer Spectroscopy
/ Unzueta, Iraultza (Basque U., Bilbao) ; Gunnlaugsson, Haraldur Pall (Iceland U.) ; Mølholt, Torben Esmann (CERN) ; Masenda, Hilary (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Mokhles Gerami, Adeleh (IPM, Tehran) ; Krastev, Petko (Sofiya, Inst. Nucl. Res.) ; Zyabkin, Dmitry V (Ilmenau Tech. U.) ; Bharuth-Ram, Krish (KwaZulu Natal U.) ; Naidoo, Deena (U. Witwatersrand, Johannesburg, Sch. Phys.) ; Ólafsson, Sveinn (Iceland U.) et al.
The magnetic properties of MnxGa alloys critically depend on compositionx, andthe atomic-scale origin of those dependences is still not fully disclosed. Molecularbeam epitaxy has been used to produce a set of MnxGa samples (x¼0.7÷1.9)with strong perpendicular magnetic anisotropy, and controllable saturationmagnetization and coercivefield depending onx. [...]
2022 - 11 p.
- Published in : Phys. Status Solidi B 259 (2022) 2200121
Fulltext: PDF;
|
|