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ABSTRACT: Self-organized nanostripes are observed in various light-rare-earth (LRE)-based 123-type high-Tc superconductors in the as-grown state by means of AFM and STM topography measurements. These observations indicate that the nanostripes are formed during the crystal growth process. The necessary oxygenation step to obtain superconducting samples causes the formation of twin boundaries and thus, deforms the original arrangement of the nanostripes.
Physica C Superconductivity 01/2011; 471:66. · 1.01 Impact Factor
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ABSTRACT: The microtexture of differently prepared Ba-hexaferrite samples is investigated by means of electron backscatter diffraction (EBSD). Kikuchi patterns are obtained with a high image quality, enabling a spatial resolution of the EBSD maps of about 20 nm. The spatially highly resolved EBSD mappings provide additional information (individual grain orientation, misorientation angles, grain size distribution) as compared to the standard analysis techniques, which can contribute to an optimization of the growth process. Furthermore, as the crystallographic orientation of each grain is known, an exact analysis of the grain aspect ratio becomes possible which provides further insight to the microstructural dependence of the magnetic properties of ferrites.
Journal of Physics Conference Series 02/2010; 200(8):082014.
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ABSTRACT: A texture analysis is performed by means of the electron-backscatter diffraction technique (EBSD) on melt-spun ribbon-like samples of the composition Ni52.5Mn24.5Ga23 (at.-%) were prepared. A dedicated surface treatment is required in order to achieve high quality Kikuchi patterns. For this purpose, mechanical polishing plus ion polishing was employed. EBSD analysis and transmission electron microscopy revealed that the samples have a polycrystalline, granular morphology, with grain sizes around 1 – 2 μm. Several larger grains being present in the region selected for EBSD analysis, and many small grains are found, even embedded in the larger ones. The larger grains exhibit a common direction of elongation, yielding to a specific texture.
Journal of Physics Conference Series 02/2010; 200(8):082013.
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ABSTRACT: (001)- and (111)-oriented magnetite thin films were grown on MgO substrates (film thickness 200 nm) by means of oxygen-plasma-assisted molecular beam epitaxy and by laser-ablation. Further samples are electroplated magnetite thin films on Si/copper substrates and films from biogenic magnetite. The achieved grain orientations are analysed by means of the electron backscatter diffraction (EBSD) technique. The EBSD technique enables the crystallographic orientation of individual grains to be determined with a high spatial resolution of up to 40 nm on such ceramic materials. A high image quality of the recorded Kikuchi patterns was achieved enabling multi-phase scans (e.g., Fe3O4, MgO, Fe2O3). The facets of individual grains are analysed in detail.
Journal of Physics Conference Series 02/2010; 200(7):072053.
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ABSTRACT: The analysis of the achieved texture is of great importance for the performance of ferrite materials,
either bulk or thin films. The recently developed electron backscatter diffraction (EBSD) technique
enables a spatially resolved study of the crystallographic orientations by means of recording of Kikuchi
patterns. To our knowledge, such a thorough EBSD analysis was not yet performed in any oxidic
magnetic material, and only very recently on magnetite thin films by us. A good surface polishing/
cleaning is essential for this analysis, as the method requires an undisturbed surface area for a high
image quality (IQ). This information is recorded to each measured Kikuchi pattern, together with a
parameter describing the quality of indexation. Here, the spatially highly resolved EBSD mappings
provide additional information as compared to the standard analysis techniques, which can contribute
to an optimization of the growth process. Furthermore, an analysis of the grain aspect ratio is possible
which provides further insight to the microstructural dependence of the magnetic properties of ferrites
Journal of Magnetism and Magnetic Materials 01/2010; 322:1178. · 1.78 Impact Factor
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Journal of Magnetism and Magnetic Materials. 01/2010; 322(9-12):1235-1238.
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Thin Solid Films. 01/2010; 518(16):4730-4733.
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Thin Solid Films. 01/2010; 518(16):4734-4737.
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Koblischka,
MR (Koblischka,
M. R,
Koblischka-Veneva, A (Koblischka-Veneva,
A,
Wick,
M (Wick,
M,
Mitoseriu,
L (Mitoseriu,
L,
Hartmann,
U (Hartmann,
U
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ABSTRACT: The microstructures of composite xBaTiO(3)-(1-x)(Ni(0.5)Zn(0.5))Fe(2)O(4) (BT-NZF) multiferroics with various mixing ratios (x = 0.50, 0.60 and 0.70) are investigated by means of electron backscatter diffraction (EBSD) and magnetic force microscopy (MFM). The EBSD measurements reveal a change in the texture of the ferrite and the BaTiO(3) grains upon increasing the ferrite content in the sample. The sample with x = 0.70 exhibits the best ferrite texture, where only some directions are present. Furthermore, the resulting grain sizes vary from several pm (x = 0.50) to about 100 nm in the sample with x = 0.70. The MFM images reveal the presence of magnetic domains being extended over several adjacent grains, which according to the EBSD data may comprise different crystallographic orientations. In this way, we can explain the differences in the magnetic contrast obtained. (C) 2009 Elsevier B.V. All rights reserved.
Thin Solid Films. 01/2010; 518:4730-33.
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ABSTRACT: The electron backscatter diffraction (EBSD) technique enables an advanced analysis of anisotropic materials like ferrites. Here, the spatially highly resolved EBSD mappings provide additional information as compared to the standard analysis techniques, which can contribute to an optimization of the growth process. Furthermore, an analysis of the grain aspect ratio is possible which provides further insight to the microstructural dependence of the magnetic properties of ferrites.
IEEE Transactions on Magnetics 11/2009; · 1.36 Impact Factor
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ABSTRACT: Nanorods of goethite, i.e. alpha-FeOOH, were mixed with BaCO3, dispersed in a polymer solution, and oriented under a 90 kOe magnetic field during polymerization. The orientation arose principally from the interaction of the magnetic field with the anisotropic antiferromagnetism of the goethite particles. The oriented antiferromagnetic particles act as seeds for the topochemical growth of BaFe12O19 ferrite grains along the [0001] direction. The degree of grain orientation was determined using magnetic measurements and orientation distribution functions and pole figures determined by electron backscatter diffraction analysis.
Nanotechnology 11/2009; 20(44):445606. · 3.98 Impact Factor
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ABSTRACT: a b s t r a c t Nanostripes are observed in melt-textured and single-crystalline samples of the ternary light rare earth (LRE)-compound (Nd 0.33 Eu 0.33 Gd 0.33)Ba 2 Cu 3 O x (NEG) by means of atomic force microscopy, scanning tun-nelling microscopy at ambient conditions, combined with transmission electron microscopy and electron backscatter diffraction. This enables the observation of several important features: The nanostripes are formed by chains of nanoclusters, representing the LRE/Ba substitution. The dimensions of the nano-stripes are similar for both types of NEG samples. The periodicity of the nanostripes is found to range between 40 and 60 nm; the shape of the nanoclusters is elliptic with a major axis length between 300 and 500 nm and a minor axis length of about 30–150 nm. The stripes are filling effectively the space in between the twin boundaries. Concerning the flux pinning, the nanoclusters are the important pinning sites, not the nanostripes themselves.
Bd. 02/2009; 8181(74).
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[show abstract]
[hide abstract]
ABSTRACT: The electron backscatter diffraction (EBSD) technique enables an advanced analysis of anisotropic materials like ferrites. Here, the
spatially highly resolved EBSD mappings provide additional information as compared to the standard analysis techniques, which can
contribute to an optimization of the growth process. Furthermore, an analysis of the grain aspect ratio is possible which provides further
insight to the microstructural dependence of the magnetic properties of ferrites.
IEEE Transactions on Magnetics 01/2009; 45:4219. · 1.36 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Nanostripes are observed in melt-textured and single-crystalline samples of the ternary light rare earth
(LRE)-compound (Nd0.33Eu0.33Gd0.33)Ba2Cu3Ox (NEG) by means of atomic force microscopy, scanning tunnelling
microscopy at ambient conditions, combined with transmission electron microscopy and electron
backscatter diffraction. This enables the observation of several important features: The nanostripes are
formed by chains of nanoclusters, representing the LRE/Ba substitution. The dimensions of the nanostripes
are similar for both types of NEG samples. The periodicity of the nanostripes is found to range
between 40 and 60 nm; the shape of the nanoclusters is elliptic with a major axis length between 300
and 500 nm and a minor axis length of about 30–150 nm. The stripes are filling effectively the space
in between the twin boundaries. Concerning the flux pinning, the nanoclusters are the important pinning
sites, not the nanostripes themselves.
Physica C Superconductivity 01/2009; 469:168. · 1.01 Impact Factor
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IEEE Transactions on Magnetics. 01/2009; 45(10):4219-4222.
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Physica C-Superconductivity and Its Applications. 01/2009; 469(4):168-176.
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ABSTRACT: The properties of grain boundaries within Ag-clad (Pb,Bi)2Sr2Ca2Cu3Ox (Bi-2223) tapes are studied by means of electron backscatter diffraction (EBSD). The achieved high image quality of the Kikuchi patterns enables multi-phase EBSD scans including Bi-2223, Bi2Sr2CaCu2Ox (Bi-2212), Bi2Sr2CuOx (Bi-2201), (Sr,Ca)14Cu24O41 and Ag to be performed. For the EBSD scans a maximum spatial resolution of 30 nm was reached enabling a detailed orientation analysis. The nature of the grain boundaries is discussed on the base of the EBSD data. While the main orientation of the tape is in [0 0 1] direction, a large number of misorientations is detected. These misorientations are visualized using crystal direction (CD) maps. Furthermore, EBSD enables the spatially resolved mapping of the misorientation angles within each phase separately. The influence of these grain boundaries on the current transport properties is discussed.
Journal of Physics Conference Series 02/2008; 94(1):012011.
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Physica Status Solidi a-Applications and Materials Science. 01/2008; 205(8):1783-1786.
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Materials Science and Engineering B-Advanced Functional Solid-State Materials. 01/2008; 151(1):60-64.
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Materials Science and Engineering B-Advanced Functional Solid-State Materials. 01/2008; 151(1):74-78.
