| 1. |
- Wagner, W, et al.
(författare)
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Europe ambivalent on biotechnology
- 1997
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Ingår i: Nature. - London : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 387, s. 845-847
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Tidskriftsartikel (refereegranskat)abstract
- The Eurobarometer on Biotechnology (46.1) was conducted during October and November 1996. The survey conducted in each EU (European Union) country used a multi-stage random sampling procedure and provided a statistically representative sample of national residents aged 15 and over. The total sample within the EU was 16,246 respondents (about 1,000 per EU country). The survey questionnaire was designed by the authors as part of a larger study involving the comparative analysis of public perceptions, media coverage and public policy in relation to biotechnology from 1973 to the present.
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| 2. |
- Lawniczak-Jablonska, Krystyna, et al.
(författare)
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Magnetic properties of MnSb inclusions formed in GaSb matrix directly during molecular beam epitaxial growth
- 2011
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 109:7
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Tidskriftsartikel (refereegranskat)abstract
- Despite of intensive search for the proper semiconductor base materials for spintronic devices working at room temperature no appropriate material based on ferromagnetic semiconductors has been found so far. We demonstrate that the phase segregated system with MnSb hexagonal inclusions inside the GaSb matrix, formed directly during the molecular beam epitaxial growth reveals the ferromagnetic properties at room temperature and is a good candidate for exploitation in spintronics. Furthermore, the MnSb inclusions with only one crystalline structure were identified in this GaMn:MnSb granular material. The SQUID magnetometry confirmed that this material exhibits ferromagnetic like behavior starting from helium up to room temperature. Moreover, the magnetic anisotropy was found which was present also at room temperature, and it was proved that by choosing a proper substrate it is possible to control the direction of easy axis of inclusions' magnetization moment between in-plane and out-of-plane; the latter is important in view of potential applications in spintronic devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3562171]
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| 3. |
- Lawniczak-Jablonska, K., et al.
(författare)
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Structural and magnetic properties of GaAs:(Mn,Ga)As granular layers
- 2011
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Ingår i: Physica Status Solidi. B: Basic Research. - : Wiley. - 0370-1972. ; 248:7, s. 1609-1614
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Tidskriftsartikel (refereegranskat)abstract
- Granular GaAs:(Mn,Ga)As films were prepared by annealing the Ga0.92Mn0.08As/GaAs layer grown by the MBE method at low temperature. The annealing was performed at 500 or 600 degrees C. It is commonly accepted that this processing should result in formation of cubic zinc blende or hexagonal MnAs inclusions depending on the temperature. We demonstrate that such a priory assumption is not justified. The kind of formed inclusions depends not only on the annealing temperature but also on the number of defects and Mn atoms in the substitutional and interstitial positions in as grown sample. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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| 4. |
- Lawniczak-Jablonska, K., et al.
(författare)
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Structural and magnetic properties of nanoclusters in GaMnAs granular layers
- 2011
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596. ; 184:6, s. 1530-1539
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Tidskriftsartikel (refereegranskat)abstract
- Structural and magnetic properties of GaAs thin films with embedded nanoclusters were investigated as a function of the annealing temperature and Mn content. Surprisingly, the presence of two kinds of nanoclusters with different structure was detected in most of the samples independently of the thermal processing or Mn content. This proved that the presence of a given type of clusters cannot be assumed a priori as is reported in many papers. The fraction of Mn atoms in each kind of cluster was estimated from the extended X-ray absorption fine structure analysis. This analysis ruled out the possibility of the existence of nanoclusters containing a hypothetic MnAs cubic compound-only (Ga,Mn)As cubic and hexagonal MnAs clusters were detected. Moreover the bimodal distribution of Mn magnetic moments was found, which scales with the estimated fraction of Mn atoms in the cubic and hexagonal clusters. (C) 2011 Elsevier Inc. All rights reserved.
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| 5. |
- Lawniczak-Jablonska, Krystyna, et al.
(författare)
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Structural and magnetic properties of the molecular beam epitaxy grown MnSb layers on GaAs substrates
- 2009
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 106:8
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Tidskriftsartikel (refereegranskat)abstract
- The structural and magnetic properties of MnSb layers grown on two differently oriented GaAs substrates are reported. The MnSb compounds grow nonhomogenously both on GaAs (111) B and on GaAs (100) substrates. In x-ray diffraction studies the formation of two epitaxial domains is observed depending on the crystallographic orientation of the substrate. The observed diffusion of Ga atoms from the substrate to the layers results in the formation of an additional Mn-rich cubic phase of GaMnSb. In the case of the (100) oriented substrate, the diffusion of Mn into the substrate was additionally found. Traces of other phases were also noticed. The complex morphology of the layers is found to influence their magnetic properties. Magnetic force microscopy images revealed an inhomogenous distribution of the magnetic force gradient on the surface and the formation of magnetic domains in the samples. X-ray absorption studies of the chemical bonding and local atomic structure around Mn atoms confirmed high structural and chemical disorder in the samples. The chemical bonding of the dominating fraction of Mn atoms is found, however, similar to that in the reference MnSb powder. The x-ray magnetic circular dichroism measurements reveal an enhanced orbital moment and a reduced spin moment, which is most likely caused by the presence of different phases and a Mn-rich surface in the investigated samples.
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| 6. |
- Lawniczak-Jablonska, K., et al.
(författare)
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The source of room temperature ferromagnetism in granular GaMnAs layers with zinc blende clusters
- 2011
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Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254. ; 5:2, s. 62-64
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Tidskriftsartikel (refereegranskat)abstract
- Granular GaAs:(Mn,Ga) As films were prepared by annealing the Ga0.985Mn0.015As/GaAs layers at 500 degrees C or 600 degrees C. It is commonly accepted that this processing should result in the formation of cubic or hexagonal MnAs clusters, respectively. We demonstrate that such a priori assumption is not justified. If in the as grown sample there are not many defects with the interstitial Mn atoms, only small cubic clusters can be formed even after annealing at 600 degrees C. Moreover, in a sample containing solely cubic GaMnAs clusters, the Mn ions are ferro-magnetically coupled at room temperature. This fact was explained by the existence of GaMnAs solid solution in the clusters, with content of Mn close to 20% (higher than ever found in the layers) as was confirmed by experiment and theory. Extended X-ray absorption spectroscopy studies excluded the possibility of formation of the hypothetic zinc blende MnAs clusters. Not more than one Mn atom was detected in the second shell around central Mn atom. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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