Structural and Magnetic Properties of Epitaxial Co-Au Superlattices

1989 ◽  
Vol 151 ◽  
Author(s):  
C. H. Lee ◽  
Hui He ◽  
F. Lamelas ◽  
W. Vavra ◽  
C. Uher ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Molecular Beam ◽  
Easy Axis ◽  
Constant Thickness ◽  
Substrate Plane ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Axis Parallel ◽  
Structural And Magnetic Properties

ABSTRACTWe describe measurements on the structural and magnetic properties of Co–Au superlattices grown on Ge–buffered (110) GaAs by molecular beam epitaxy. Samples have been prepared with Co layer thicknesses ranging from 5–40Å and Au spacer layers of constant thickness, ∼ 16Å. X–ray scattering and high-resolution transmission electron microscopy show that the hcp Co layers grow epitaxially with the (0001) axis parallel to (111)Au and with the in–plane Co[1120] axis parallel to GaAs[001]. SQUID magnetometer measurements reveal a crossover in the magnetic anisotropy of the as–grown samples such that the easy axis is perpendicular to the substrate plane when the Co layer thickness is less than ∼19Å.

Epitaxial Co-Cu Superlattices

1991 ◽  
Vol 231 ◽  
Author(s):  
Elizabeth Schuler ◽  
Sezai Elagoz ◽  
William Vavra ◽  
Frank Lamelas ◽  
Hui David He ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Molecular Beam Epitaxy ◽  
Layer Thickness ◽  
Molecular Beam ◽  
Antiferromagnetic Coupling ◽  
Competing Interactions ◽  
X Ray ◽  
X Ray Scattering ◽  
Complex Spin

AbstractWe describe measurements on the magnetic properties of Co-Cu superlattices in which the Co layer thickness was fixed at 20 Å and the Cu thickness was varied from 4 Å to 24 Å. The samples were grown on Ge-buffered (110) GaAs by molecular beam epitaxy. X-ray scattering and in-situ RHEED indicate that the multilayers are oriented in the (111) direction with the Co layers stacked in an fcc arrangement. Our interest in this series of samples lies in their unusual hysteresis curves which show distinct transitions. We have found that the appearance of these transitions is directly related to the Cu thickness, indicating the presence of complex spin configurations as a consequence of competing interactions. The results are not consistent with a simple RKKY antiferromagnetic coupling.

EFFECT OF SAMARIUM DOPING ON THE STRUCTURAL AND MAGNETIC PROPERTIES OF THE LITHIUM–NICKEL FERRITE

2008 ◽  
Vol 22 (21) ◽  
pp. 2027-2033 ◽  
Author(s):  
LUNHONG AI ◽  
JING JIANG ◽  
HEJUN GAO
Keyword(s):  
Magnetic Properties ◽  
Nickel Ferrite ◽  
Spinel Phase ◽  
Lattice Parameter ◽  
Particle Sizes ◽  
Vibrating Sample Magnetometer ◽  
Soft Chemistry ◽  
X Ray ◽  
Transmission Electron ◽  
Structural And Magnetic Properties

Sm -doped Li – Ni ferrites were synthesized by a soft chemistry method. The effects of Sm -doping on the structural and magnetic properties of the Li – Ni ferrites were investigated. The structural, morphological and magnetic properties of the ferrite samples were characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The results revealed that the Sm -doped samples had the single spinel phase at low Sm content. The increase in Sm content increased the lattice parameter and decreased the particle sizes. The magnetic properties of the Sm -doped Li – Ni ferrites were strongly affected by Sm content. The saturation magnetization decreased, while coercivity increased with increasing Sm content.

scholarly journals Structural and magnetic properties of iron nanowires and iron nanoparticles fabricated through a reduction reaction

2015 ◽  
Vol 6 ◽  
pp. 1652-1660 ◽  
Author(s):  
Marcin Krajewski ◽  
Wei Syuan Lin ◽  
Hong Ming Lin ◽  
Katarzyna Brzozka ◽  
Sabina Lewinska ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Iron Nanoparticles ◽  
Reduction Reaction ◽  
Structural Investigations ◽  
X Ray ◽  
Transmission Electron ◽  
Structural And Magnetic Properties ◽  
Iron Nanowires ◽  
Means Of Transmission

The main goal of this work is to study the structural and magnetic properties of iron nanowires and iron nanoparticles, which have been fabricated in almost the same processes. The only difference in the synthesis is an application of an external magnetic field in order to form the iron nanowires. Both nanomaterials have been examined by means of transmission electron microscopy, energy dispersive X-ray spectrometry, X-ray diffractometry and Mössbauer spectrometry to determine their structures. Structural investigations confirm that obtained iron nanowires as well as nanoparticles reveal core–shell structures and they are composed of crystalline iron cores that are covered by amorphous or highly defected phases of iron and iron oxides. Magnetic properties have been measured using a vibrating sample magnetometer. The obtained values of coercivity, remanent magnetization, saturation magnetization as well as Curie temperature differ for both studied nanostructures. Higher values of magnetizations are observed for iron nanowires. At the same time, coercivity and Curie temperature are higher for iron nanoparticles.

EFFECTS OF HIGH MAGNETIC FIELD ON THE STRUCTURAL EVOLUTION AND MAGNETIC PROPERTIES OF NANOCRYSTALLINE Ni FILMS

NANO ◽  
2014 ◽  
Vol 09 (02) ◽  
pp. 1450025 ◽  
Author(s):  
JIAOJIAO DU ◽  
GUOJIAN LI ◽  
QIANG WANG ◽  
YONGZE CAO ◽  
YONGHUI MA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
High Magnetic Field ◽  
Molecular Beam ◽  
Structural Evolution ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Atomic Force ◽  
Transmission Electron ◽  
Quartz Substrates

This paper studies the effects of a high magnetic field on the structural evolution and magnetic properties of nanocrystalline Ni films prepared on quartz substrates by a molecular beam vapor deposition (MBVD) method. Atomic force microscope, X-ray diffractometer, transmission electron microscope and vibrating sample magnetometer were used to study the microstructures and magnetic properties of the Ni films. The results indicate that high magnetic field has no obvious influence on crystal structures except changing the lattice constant of the Ni films. However, the high magnetic field can refine particle size. The film deposited under magnetic field tends to grow through columnar mode because of the magnetized particles aligning along the direction of magnetic field. Furthermore, the ordered and dense arrangement of Ni atoms results in more spins contained in per unit volume and improves the saturation magnetization (Ms). Ms of the 6 T Ni film increases by 70% (578 emu/cm3) than that of the film without magnetic field (341 emu/cm3), and the coercivity is also slightly increased for the 6 T film.

scholarly journals Reversible magnetism switching of iron oxide nanoparticle dispersions by controlled agglomeration

2021 ◽  
Author(s):  
Stephan Müssig ◽  
Björn Kuttich ◽  
Florian Fidler ◽  
Daniel Haddad ◽  
Susanne Wintzheimer ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Light Scattering ◽  
Superparamagnetic Iron Oxide ◽  
Iron Oxide Nanoparticle ◽  
Oxide Nanoparticles ◽  
X Ray ◽  
X Ray Scattering ◽  
Nanoparticle Dispersions ◽  
Oxide Nanoparticle

The controlled agglomeration of superparamagnetic iron oxide nanoparticles (SPIONs) was used to rapidly switch their magnetic properties. Small-angle X-ray scattering (SAXS) and dynamic light scattering showed that tailored iron oxide...

scholarly journals Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3096-3104
Author(s):  
Valeria Castelletto ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Ian W. Hamley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ph Dependent ◽  
Ray Scattering

A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties.

On the selective aerobic oxidation of benzyl alcohol with Pd/Au-nanoparticles in batch and flow

2014 ◽  
Vol 3 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Hannes Alex ◽  
Norbert Steinfeldt ◽  
Klaus Jähnisch ◽  
Matthias Bauer ◽  
Sandra Hübner
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Aerobic Oxidation ◽  
X Ray ◽  
X Ray Scattering ◽  
Oxidation Of Benzyl Alcohol ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Selective Aerobic Oxidation

AbstractNanoparticles (NP) have specific catalytic properties, which are influenced by parameters like their size, shape, or composition. Bimetallic NPs, composed of two metal elements can show an improved catalytic activity compared to the monometallic NPs. We, herein, report on the selective aerobic oxidation of benzyl alcohol catalyzed by unsupported Pd/Au and Pd NPs at atmospheric pressure. NPs of varying compositions were synthesized and characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The NPs were tested in the model reaction regarding their catalytic activity, stability, and recyclability in batch and continuous procedure. Additionally, in situ extended X-ray absorption fine structure (EXAFS) measurements were performed in order to get insight in the process during NP catalysis.

An X-ray scattering study on inverted Ge–Si huts grown at low temperatures

2004 ◽  
Vol 19 (4) ◽  
pp. 347-351
Author(s):  
J. Xu ◽  
X. S. Wu ◽  
B. Qian ◽  
J. F. Feng ◽  
S. S. Jiang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Lattice Strain ◽  
Lattice Mismatch ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Large Lattice ◽  
Scattering Study

Ge–Si inverted huts, which formed at the Si∕Ge interface of Si∕Ge superlattice grown at low temperatures, have been measured by X-ray diffraction, grazing incidence X-ray specular and off-specular reflectivities, and transmission electron microscopy (TEM). The surface of the Si∕Ge superlattice is smooth, and there are no Ge–Si huts appearing on the surface. The roughness of the surfaces is less than 3 Å. Large lattice strain induced by lattice mismatch between Si and Ge is found to be relaxed because of the intermixing of Ge and Si at the Si∕Ge interface.

Analysis of InGaN/GaN single quantum wells by X-ray scattering and transmission electron microscopy

2003 ◽  
Vol 240 (2) ◽  
pp. 297-300 ◽  
Author(s):  
T. M. Smeeton ◽  
M. J. Kappers ◽  
J. S. Barnard ◽  
M. E. Vickers ◽  
C. J. Humphreys
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Wells ◽  
Single Quantum ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ray Scattering

Structural characterization of laser ablated epitaxial (Ba0.5Sr0.5)TiO3 thin films on MgO(001) by synchrotron x-ray scattering

1999 ◽  
Vol 14 (7) ◽  
pp. 2905-2911 ◽  
Author(s):  
Sangsub Kim ◽  
Tae Soo Kang ◽  
Jung Ho Je
Keyword(s):  
Thin Films ◽  
Early Stage ◽  
Lattice Parameter ◽  
Normal Direction ◽  
X Ray ◽  
X Ray Scattering ◽  
Surface Normal ◽  
Out Of Plane ◽  
Axis Parallel ◽  
Ray Scattering

Epitaxial (Ba0.5Sr0.5) TiO3 thin films of two different thickness (∼25 and ∼134 nm) on MgO(001) prepared by a pulsed laser deposition method were studied by synchrotron x-ray scattering measurements. The film grew initially with a cube-on-cube relationship, maintaining it during further growth. As the film grew, the surface of the film became significantly rougher, but the interface between the film and the substrate did not. In the early stage of growth, the film was highly strained in a tetragonal structure (c/a = 1.04) with the longer axis parallel to the surface normal direction. As the growth proceeded further, it relaxed to a cubic structure with the lattice parameter near the bulk value, and the mosaic distribution improved significantly in both in- and out-of-plane directions. The thinner film (∼25 nm) showed only one domain limited mainly by the film thickness, but the thicker film (∼134 nm) exhibited three domains along the surface normal direction.

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