Magnetic Anisotropy and Lattice Distortions in The Doped Perovskite Manganites

1997 ◽  
Vol 494 ◽  
Author(s):  
Y. Suzuki ◽  
H. Y. Hwang ◽  
S-W. Cheong ◽  
R. B. Van Dover ◽  
A. Asamitsu ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Lattice Mismatch ◽  
Crystal Form ◽  
Epitaxial Films ◽  
Perovskite Manganites ◽  
X Ray Diffraction ◽  
Epitaxial Thin Film ◽  
X Ray ◽  
Atomic Force ◽  
Lattice Distortions

ABSTRACTWe have investigated the magnetic anisotropies of doped manganite materials in epitaxial thin film and single crystal form. Structural characterization, including x-ray diffraction, Rudierford backscattering spectroscopy and atomic force misocroscopy, indicate that our epitaxial films arc single crystalline and have excellent crystallinity. Since lattice distortions greatly affect the magnetic and transport properties of this family of materials, it is not surprising to find the profound effect of strain in films due to the lattice mismatch between the substrate and film. Magnetic anisotropy results of single crystals, subject to no external stress, is compared to those of epitaxial films.

Preparation and Research on the Lateral Elastic Modulus of the MnO2 Nanowires

2013 ◽  
Vol 662 ◽  
pp. 84-87
Author(s):  
Yong Jiang ◽  
Jian Cheng Deng ◽  
Yan Huai Ding ◽  
Jiu Ren Yin ◽  
Ping Zhang
Keyword(s):  
Elastic Modulus ◽  
Crystal Form ◽  
Bending Test ◽  
X Ray Diffraction ◽  
Nanowire Diameter ◽  
X Ray ◽  
Three Point Bending ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mno2 Nanowires

MnO2 nanowires with large aspect ratio were successfully synthesized via a hydrothermal method. In this method, Mn(NO3)2 was as a source of manganese and NH4NO3 as an oxidant. The structure and morphology of the MnO2 nanowires were characterized by X ray diffraction (XRD) and scanning electron microscope (SEM). Their lateral elastic modulus was characterized via a nanoscale three-point bending test by atomic force microscopy (AFM) equipped with picoforce. The results indicate that the crystal form of MnO2 was β-MnO2. The elastic modulus of the nanowires decreased with the increase in nanowire diameter. This elastic modulus was in the range of 33.36-77.84GPa as the diameter ranged from 240 to 185nm.

Influence of Fe on the Morphology of Spinel in the System MgO-Al2O3-Fe2O3.

2000 ◽  
Vol 654 ◽  
Author(s):  
O.V. Kharissova ◽  
U. Ortiz ◽  
M. Hinojosa
Keyword(s):  
Epitaxial Films ◽  
Catalytic Reactions ◽  
General Interest ◽  
X Ray Diffraction ◽  
Contact Mode ◽  
Surface Conditions ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Conventional Furnace

AbstractThe investigation of the morphology of crystalline solids surfaces is of practical and general interest because many processes such as the growth of epitaxial films, catalytic reactions and others, are intimately connected with surface conditions. In this work we study the surface morphology and structure of the spinel as produced in the system MgO- Al2O3-Fe2O3 at 1400°C for 15 h in a conventional furnace and in a microwave oven for 30 min. The spinel was analyzed by X-ray diffraction, scanning electron microscopy (SEM), X-ray spectrometry (EDX), and atomic force microscopy (AFM). The AFM images were recorded in the contact mode. Images scanned at different magnifications show steps and flat terraces. Experimental observations were made on the nature and distribution of the observed polygonal morphology.

Growth of epitaxial films of sodium potassium tantalate and niobate on single-crystal lanthanum aluminate [100] substrates

2008 ◽  
Vol 23 (12) ◽  
pp. 3281-3287 ◽  
Author(s):  
George H. Thomas ◽  
Eliot D. Specht ◽  
John Z. Larese ◽  
Ziling B. Xue ◽  
David B. Beach
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
Epitaxial Films ◽  
Metal Species ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Sodium Potassium ◽  
Potassium Tantalate ◽  
X Ray ◽  
Lanthanum Aluminate

Epitaxial films of sodium potassium tantalate (Na0.5K0.5TaO3, NKT) and sodium potassium niobate (Na0.5K0.5NbO3, NKN) were grown on single-crystal lanthanum aluminate (LAO) (100) (indexed as a pseudo-cubic unit cell) substrates via an all-alkoxide solution (methoxyethoxide complexes in 2-methoxyethanol) deposition route for the first time. X-ray diffraction studies indicated that the onset of crystallization in powders formed from hydrolyzed gel samples was 550 °C. 13C nuclear magnetic resonance studies of solutions of methoxyethoxide complexes indicated that mixed-metal species were formed, consistent with the low crystallization temperatures observed. Thermal gravimetric analysis with simultaneous mass spectrometry showed the facile loss of the ligand (methoxyethoxide) at temperatures below 400 °C. Crystalline films were obtained at temperatures as low as 650 °C when annealed in air. θ-2θ x-ray diffraction patterns revealed that the films possessed c-axis alignment in that only (h00) reflections were observed. Pole-figures about the NKT or NKN (220) reflection indicated a single in-plane, cube-on-cube epitaxy. The quality of the films was estimated via ω (out-of-plane) and φ (in-plane) scans and full-widths at half-maximum (FWHMs) were found to be reasonably narrow (∼1°), considering the lattice mismatch between the films and the substrate.

On the Epitaxy of Metal Films on GaN

1996 ◽  
Vol 449 ◽  
Author(s):  
Q.Z. Liu ◽  
K.V. Smith ◽  
E.T. Yu ◽  
S.S. Lau ◽  
N.R. Perkins ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lattice Mismatch ◽  
Metal Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Determining Factor

ABSTRACTA variety of metal films deposited at room temperature have been found to grow epitaxially under conventional vacuum conditions on GaN grown by metalorganic vapor phase epitaxy on sapphire substrates. The metal films have been characterized by X-ray diffraction using a thin-film Read camera and by MeV ion channeling measurements. Lattice mismatch between the epitaxial metals and the GaN basal planes ranges from ∼ 0.2% to ∼ 22%, and does not appear to be the determining factor in the epitaxy reported here. Surface structure of the epitaxial metal films has been studied by atomic force microscopy and found to differ considerably from that of nonepitaxial metal films grown on similar GaN substrates.

scholarly journals Structural Studies of the Epitaxial Layer of a Substitutional Solid Solution (GaAs)1−x(ZnSe)x with Nanocrystals

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
A. S. Saidov ◽  
Sh. N. Usmonov ◽  
D. V. Saparov
Keyword(s):  
Solid Solution ◽  
Epitaxial Layer ◽  
Surface Region ◽  
Substitutional Solid Solution ◽  
Epitaxial Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ordered Array

In this work, we explored the possibility of growing a substitutional solid solution (GaAs)1−x(ZnSe)x with an ordered array of nanosize crystals on GaAs (100) substrates. Grown epitaxial films were investigated by the X-ray diffraction analysis method. The chemical composition of the grown epitaxial films was determined by a X-ray microanalyzer, along the thickness of the epitaxial layer. The photoluminescence spectrum was studied and a peak is observed at λmax = 465 nm, corresponding to the width of the band gap of zinc selenide EZnSe = 2.67 eV, which is apparently due to the nanocrystals ZnSe, disposed in the surface region of the epitaxial film of a solid solution (GaAs)1−x(ZnSe)x. Size of nanocrystals were evaluated by an atomic force microscopy.

Threading dislocations in domain-matching epitaxial films of ZnO

2007 ◽  
Vol 40 (5) ◽  
pp. 924-930 ◽  
Author(s):  
W.-R. Liu ◽  
W. F. Hsieh ◽  
C.-H. Hsu ◽  
Keng S. Liang ◽  
F. S.-S. Chien
Keyword(s):  
Gas Flow ◽  
Epitaxial Films ◽  
Zno Films ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Transmission Electron ◽  
Edge Dislocations

The structures of high-quality ZnO epitaxial films grown by pulsed-laser deposition on sapphire (0001) without an oxygen gas flow were investigated by X-ray diffraction and transmission electron microscopy. The great disparity of X-ray diffraction line widths between the normal and in-plane reflections reveals the specific threading dislocation geometry of ZnO. Most threading dislocations are pure edge dislocations. From a combination of scattering and microscopic results, it is found that threading dislocations are not uniformly distributed in the ZnO films, but the films consist of columnar epitaxial cores surrounded by annular regions of edge threading dislocations in large density. The local surface morphology and capacitance signal obtained from atomic force and scanning capacitance microscopes indicate that the aggregation of threading dislocations leads to high interface traps at the annular regions.

MBE Growth of GaN on NdGaO3 (101)

1997 ◽  
Vol 482 ◽  
Author(s):  
C. Fechtmann ◽  
V. Kirchner ◽  
S. Einfeldt ◽  
H. Heinke ◽  
D. Hommel ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
High Energy ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
Mbe Growth ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Relationship Of ◽  
Interesting Alternative

AbstractWe report on the growth of GaN on NdGaO3 (101) by plasma assisted molecular beam epitaxy (MBE). NdGaO3 (101) is an interesting alternative substrate compared to A12O3 due to its smaller lattice mismatch of +1.2 % to hexagonal (0001) GaN. Using photoluminescence (PL), X-ray diffraction (XRD), reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM) the optical and structural properties of the GaN thin films grown on NdGaO3 are investigated and compared to those grown on c-plane sapphire. The intended epitaxial relationship of [0001] GaN ║ [101] GaN is hard to realise as confirmed by several tilted or even polycrystalline films. However, the layer quality was found to improve considerably, when the NdGaO3 surface showed a (l × 1) instead of other reconstructions.

Preparation and comparison of YBa2Cu4O8 films on MgO(100) and SrTiO3(100) by MOCVD

1993 ◽  
Vol 8 (9) ◽  
pp. 2143-2148 ◽  
Author(s):  
H. Sakai ◽  
Y. Shiohara ◽  
S. Tanaka
Keyword(s):  
Electron Microscopy ◽  
Lattice Mismatch ◽  
Film Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
The Difference ◽  
Xrd Patterns

The thin films (Y/Ba/Cu = 1.0/2.7/4.7) which have a strong intensity corresponding to the c-axis peaks of the 124 phase (YBa2Cu4O8) in x-ray diffraction (XRD) patterns were prepared. The film structure and surface morphology of these films were observed by scanning electron microscopy (SEM), energy dispersive x-ray (EDX), transmission electron microscopy (TEM), and atomic force microscopy (AFM). It was found that the film on MgO(100) clearly has grain boundaries with many a-axis oriented grains of the 123 phase (YBa2Cu3O7−x). However, the film on SrTiO3(100) had a smooth surface, and a-axis oriented grains of the 123 phase couldn't be observed. This difference could not be explained by only the difference in the lattice mismatch.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

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