Synthesis and Properties of Ultra-Thin YBa2Cu3O7 and YBa2Cu3O7/La2-xSrxCuO4 Multilayers

1989 ◽  
Vol 169 ◽  
Author(s):  
C.B. Eom ◽  
S.K. Streiffer ◽  
J.Z. Sun ◽  
K. Yamamoto ◽  
S.S. Laderman ◽  
...  
Keyword(s):  
Single Layer ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Superconducting Thin Film ◽  
Cross Sectional ◽  
X Ray ◽  
Single Target ◽  
Modulation Wavelength

AbstractUsing our standard single target off-axis sputter deposition procedure[1], ultra-thin YBa2Cu3O7 superconducting films were made in-situ. We have studied the thickness dependence of superconducting properties (Tc, Jc) from 20 to 5000Å. Tc starts degrading below 125Å and falls to 50 K for the 30 Å film. Jc drops linearly with decreasing thickness below l000Å. We have grown YBa2Cu3O7/La2-xSrxCuO4 superconducting thin film multilayers in-situ by the same process. The modulation wavelength of the multilayers ranged from 45Å to 2000Å. X-ray diffraction and cross sectional TEM confirm the superlattice periodicity. The superconducting transition temperature drops in much the same way as the single layer ultra-thin films. Both the critical current density and its magnetic field dependence decrease as the modulation wavelength decreases.

Investigation of Magnetic Order in Iron Oxide-Nickel Oxide Superlattices with Modulation Wavelength Less Than 80 Å

1991 ◽  
Vol 231 ◽  
Author(s):  
S. D. Berry ◽  
D. M. Lind ◽  
G. Chern ◽  
H. Mathias ◽  
L. R. Testardi
Keyword(s):  
Magnetic Order ◽  
Spontaneous Magnetization ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
X Ray ◽  
Long Wavelength ◽  
Saturation Moment ◽  
Very High ◽  
Modulation Wavelength

AbstractWe have investigated the magnetic order, using SQUID magnetometry, for short modulation wavelength Fe3O4/NiO superlattices, grown on single crystal MgO. Ferrimagnetic Fe3O4 has a saturation moment of ~500 emu/cm3 at 0 K and a Curie temperature of 858 K, while bulk NiO is antiferromagnetic with a NMel temperature of 525 K. Very high crystalline quality with little interdiffusion is indicated by X-ray diffraction, SEM, optical microscopy, and in-situ RHEED, and the samples show highly anisotropic electrical conductivity which also indicates the strong modulation present. Long wavelength samples (Amod > 200 Å) have a behavior only slightly different from that expected from bulk Fe3O4, but for Amod<80 Å, spontaneous magnetization is replaced by paramagnetism, with weak temperature dependence (not I/T) from 5 K to 400 K.

Evolution of Nanoindentation Hardness of Fe/Cu Nanometer-Scale Multilayers by Magnetron Sputtering

2008 ◽  
Vol 373-374 ◽  
pp. 104-107 ◽  
Author(s):  
J. Gao ◽  
Z.L. Wu ◽  
Z.P. Zhang ◽  
B.S. Cao ◽  
M.K. Lei
Keyword(s):  
Magnetron Sputtering ◽  
Nanometer Scale ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Modulus Difference ◽  
Nanoindentation Hardness ◽  
Modulation Wavelength ◽  
Peak Value

Fe/Cu nanometer-scale multilayers with nominal modulation wavelengths ranging from 5 to 40 nm are deposited by direct current magnetron sputtering on Si (100) substrates. Modulation structures of the multilayers are examined by small angle / wide angle x-ray diffraction (SA/WAXRD) and cross-sectional transmission electron microscopy (XTEM). Hardness of the multilayers is measured by using nanoindentation. All the multilayers have Fe (110) and Cu (111) textures. Interface coherency is observed in the multilayers with designed modulation wavelengths of 5 and 10 nm. The hardness increases firstly and then deceases with increasing the modulation wavelength, and reaches peak value of 7.29±0.29 GPa in the multilayers with nominal modulation wavelength of 10 nm. The evolution of the hardness of the mulitlayers is explained by interface width and modulus difference between sublayers.

scholarly journals In situ probing of the crystallization kinetics of rr-P3HT on single layer graphene as a function of temperature

2017 ◽  
Vol 19 (12) ◽  
pp. 8496-8503 ◽  
Author(s):  
Nicolas Boulanger ◽  
Victor Yu ◽  
Michael Hilke ◽  
Michael F. Toney ◽  
David R. Barbero
Keyword(s):  
Diffraction Analysis ◽  
Crystallization Kinetics ◽  
Single Layer ◽  
Single Layer Graphene ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layer Graphene ◽  
Kinetics Of

In situ X-ray diffraction analysis of P3HT films during cooling down on both Si and G.

scholarly journals Effect of Sol-Gel Synthesized BiFeO3 Nanoparticle Addition in YBa2Cu3O7–δ (Y123) Superconductor Synthesized by Standard Solid State Reaction Method

2019 ◽  
Vol 290 ◽  
pp. 245-251
Author(s):  
Abdalla Bahboh ◽  
Abdul Halim Shaari ◽  
Hussein Baqiah ◽  
Soo Kien Chen ◽  
Mohd Mustafa Awang Kechik ◽  
...  
Keyword(s):  
Sol Gel ◽  
Solid State Reaction Method ◽  
Superconducting Transition ◽  
Secondary Phases ◽  
Superconducting Properties ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Scanning Electron Micrograph ◽  
X Ray ◽  
Pure Ybco

The effects of the multiforric BiFO3 nanoparticles addition on the structure and superconducting properties of YBa2Cu3O7–δ (Y123) with different concentrations were systematically investigated using X-ray diffraction (XRD), field emission scanning electron micrograph (FESEM), EDX and four point probe measurement. It was found that the added samples were predominant by Y-123 phase beside small amount of Y-211 and unreacted BiFeO3 secondary phases. Samples with less (wt.%) BFO added YBCO precursor powder preserved the orthorhombic structure similar to the pure YBCO, while samples with higher wt% addition show orthorhombic-to-tetragonal transition tendency. The samples became more porous and their grain size slightly decreased with addition of BiFeO3. The addition of nanoBiFeO3 disturbed the grain growth of Y123, thus resulting in the degradation of superconducting properties of the samples. The superconducting transition temperature (Tc onset) of samples decreased from 92 K for x=0.0 to 44 K for x=10.0 wt. %, which could be attributable to oxygen vacancy disorder.

The Effect of Acetate on the Electrodeposition of Manganese on Polycrystalline Au without SeO2 Additives

2014 ◽  
Vol 937 ◽  
pp. 34-40
Author(s):  
Wen Po Li ◽  
Xiu Li Zuo ◽  
Jun Ying Yang ◽  
Sheng Tao Zhang
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Quartz Crystal ◽  
Single Layer ◽  
Electrochemical Quartz Crystal Microbalance ◽  
X Ray Diffraction ◽  
Energy Dispersion Spectroscopy ◽  
X Ray ◽  
Composition And Structure ◽  
Single Layer Model

The influence of acetate additives on the mechanism of manganese electrodeposition from chloride-based acidic solution was investigated by electrochemical quartz crystal microbalance and spectroscopic ellipsometry. The EQCM data were represented as plots △m versusE.Because they are not affected by interference from the hydrogen evolution reaction, they clearly show the manganese reduction and oxidation processes. The in situ spectroscopic ellipsometry ( SE) data were analyzed with a single-layer model ( substrate Au - deposition Mn layer) and the thicknesses of Mn layer were obtained by fitting experimental data with the model.Morphology, chemical composition and structure of the manganese deposits were analyzed by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD). The results showed that in the absence of acetate additives, Mn (OH)2is formed. In the presence of acetate additives, the formation of α-Mn was observed and the deposition rate of Mn electrodeposition on the Au electrode slowed down.

dLow Temperature of formation of Nickel Germanide by reaction of Nickel and Crystalline Germanium

2014 ◽  
Vol 1655 ◽  
Author(s):  
Fahid Algahtani ◽  
Patrick W Leech ◽  
Geoffrey K Reeves ◽  
Anthony S Holland ◽  
Mark Blackford ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Annealing Temperature ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Thermal Budget ◽  
X Ray ◽  
Transmission Electron ◽  
Van Der Pauw ◽  
Heated Stage

ABSTRACTThe formation of nickel germanide has been examined over a range of low temperatures (200-400 °C) in an attempt to minimize the thermal budget for the process. Cross-sectional Transmission Electron Microscopy (TEM) was used to determine the texture of the germanide layer and the morphology and constituent composition of the Ge/NiGe interface. The onset and completion of reaction between Ni and Ge were identified by means of a heated stage in combination with in-situ x-ray diffraction (XRD) measurements. The stages of reaction were also monitored using measurements of sheet resistance of the germanides by the Van der Pauw technique. The results have shown that the minimum temperature for the initiation of reaction of Ni and Ge to form NiGe was 225 °C. However, an annealing temperature > 275 °C was necessary for the extensive (and practical) formation of NiGe. Between 200 and 300 °C, the duration of annealing required for the formation of NiGe was significantly longer than at higher temperatures. The stoichiometry of the germanide was very close to NiGe (1:1) as determined using energy dispersive spectroscopy (EDS).

Deposition of Superconducting Thin Films of Magnesium Di-Boride on Various Substrates by Electroless Plating Process

2010 ◽  
Vol 654-656 ◽  
pp. 1840-1843
Author(s):  
Susil K. Putatunda ◽  
Khurpa S. Vijayaragavan ◽  
Gavin Lawes
Keyword(s):  
Thin Films ◽  
Electroless Plating ◽  
Magnesium Diboride ◽  
Superconducting Thin Films ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Gold Silver

Superconducting thin films of magnesium diboride (MgB2) has been synthesized on various substrates such as gold, silver, copper and silicon using a novel electroless plating technique. The microstructures and the superconducting properties of these films have been characterized using X-ray diffraction, scanning electron microscopy and temperature dependent magnetometry. X-ray diffraction measurements confirm that the films are crystalline magnesium diboride with some impurity phases. Clear evidence for a superconducting transition in the magnetization measurements was observed.

In-Situ Studies of the Formation Sequence of Silicides During Vacuum (10-7 TORR)Thermal Annealing of TI/Polysilicon Bilayers

1991 ◽  
Vol 237 ◽  
Author(s):  
Z. Ma ◽  
L. H. Allen ◽  
S. Lee
Keyword(s):  
Thermal Reaction ◽  
Ex Situ ◽  
Vacuum System ◽  
X Ray Diffraction ◽  
Ramp Rate ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Film Forming

ABSTRACTThe formation of suicides during the thermal reaction of Ti/polysilicon bilayers has been investigated using both in-stu four point sheet resistance measurements and ex-situ measurements including X-ray diffraction, cross-sectional transmission electron microscopy and Auger electron spectroscopy. For a series of samples annealed at a ramp rate of 10°C/min the following sequence of changes in the bilayers occurred. At temperatures exceeding 350°C and prior to the silicidation oxygen from the vacuum system diffuses into the Ti film forming a solid solution of Ti(O) with O levels up to 20 %. An amorphous TixSiy layer is the first major suicide reaction observed at temperatures near 440°C. The first major crystalline phase is observed at 500°C and identified as C49 TiSi2. This phase was found to coexist at these temperatures with the partially consumed Ti(O) and the amorphous TixSiy layers. Further annealing above 700 °C results in the final structural transformation from C49 TiSi2 to C54 TiSi2.

Superconducting Properties of Bi-Sr-Ca-Cu-O Crystallized Glass

1999 ◽  
Vol 13 (09n10) ◽  
pp. 985-989
Author(s):  
S. Chudinov ◽  
S. Stizza ◽  
B. Kościelska ◽  
L. Murawski ◽  
W. Sadowski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Glass Ceramics ◽  
Superconducting Phase ◽  
Superconducting Transition ◽  
Resistive Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
X Ray ◽  
Quenching Method

This paper reports the crystallization and superconducting properties of Bi 4 Sr 3 Ca 3 Cu 4 O x glass-ceramics. The glass was prepared using the conventional melt-quenching method. X-ray diffraction pattern has shown that the annealing at temperature of 800°C converted the glass into glass-ceramics with Bi 2 Sr 2 CaCu 2 O x superconducting phase (2212-phase). The superconducing transition exhibits the change in the slope that is characteristic for two different superconducting phases. It is observed that T c (zero) increases from 20 K to 80 K with increasing time of annealing. The influence of magnetic field on the superconducting transition has been investigated. Our studies revealed a remarkable broadening of the resistive transition as a function of temperature with increasing field. The temperature width ( T c-T) of the transition for both phases increases with magnetic field according to Tinkham model.

Chemistry and structural modulations in Bi2Sr2CuO6

1992 ◽  
Vol 7 (4) ◽  
pp. 844-852 ◽  
Author(s):  
Y. Shen ◽  
D.R. Richards ◽  
D.G. Hinks ◽  
A.W. Mitchell
Keyword(s):  
High Temperature ◽  
Oxygen Content ◽  
Metal Ion ◽  
Ion Concentration ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Time ◽  
Structural Modulation

A series of samples along the composition lines Bi2+xSr2−xCuOy, and Bi2Sr2−xCuOy have been used to study the structural modulation, chemistry, and superconducting properties of pseudo-tetragonal Bi2Sr2CuO6 (2201). The 2201 phase can be formed from crystallization of thin glassy platelets. The sample displayed a strong crystallographic (00l) orientation which made it possible to determine incommensurate modulations near (00l) reflections using a conventional x-ray θ-2θ scan. From the crystallization of the 2201 phase, it was found that structural modulation was intrinsic to the phase, and ordering of the structure required a long time at high temperature. High temperature in situ x-ray diffraction of a 2201 Bi2Sr1.85CuOy platelet showed that the modulation existed at 875 °C in O2 (Tmelt ≍ 892 °C in O2). These suggest that the structural modulation cannot be caused solely by oxygen ordering and that metal-ion displacement must be involved. By removing 0.04 to 0.05 oxygen atom per formula unit from Bi2Sr2CuOy and Bi2Sr1.85CuOy, the c* components of the modulation changed from 0.31 to 0.26 and from 0.38 to 0.31, respectively, while the b* component of the modulation remained approximately 0.2. This demonstrates that oxygen, while not the sole cause, does play a role in the formation of the structural modulation. However, the invariance of bmod with respect to the change in oxygen content does not support the model that explained the modulation by inserting extra oxygen in the BiO plane. By varying metal-ion concentrations of Bi and Sr we found that both the lattice parameters and the modulation vectors depended more on the Bi/Sr ratio than on the Sr concentration alone. As the Bi/Sr ratio increased from 1.0 to 1.35, the modulation lines moved toward the (00l) reflections. The corresponding superstructural periodicities were calculated to vary from ∼1/5b* + 0.32 c* to ∼1/5 b* + 0.63 c*. Effects of oxygen content and metal-ion concentration on the 2201 phase formation and the superconducting properties will also be discussed.

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