Shearing single crystal magnesium in the close-packed basal plane at different temperatures

2018 ◽  
Vol 537 ◽  
pp. 162-166
Author(s):  
Ming Han ◽  
Lili Li ◽  
Guangming Zhao
Keyword(s):  
Single Crystal ◽  
Basal Plane ◽  
Different Temperatures

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

A Mössbauer study of a single crystal of the β phase of iron–germanium

1982 ◽  
Vol 60 (11) ◽  
pp. 1564-1572
Author(s):  
J. M. Daniels ◽  
H. Y. Lam ◽  
P. L. Li
Keyword(s):  
Single Crystal ◽  
Basal Plane ◽  
Mössbauer Spectra ◽  
Antiferromagnetic State ◽  
Mössbauer Study ◽  
Mossbauer Spectra ◽  
Narrow Angle ◽  
Β Phase ◽  
Line Patterns

57Fe Mössbauer spectra were obtained by scattering in a narrow angle geometry from a face, containing the basal plane, of a single crystal of the hexagonal β phase Fe1.67 Ge. Spectra were also obtained from a source of 57Co diffused into an a–c face of a single crystal of this alloy. In all cases, the spectra were satisfactorily resolved into three six-line patterns, and measurements of the relative intensities of the lines indicate that the antiferromagnetic state has a canted structure with all the spins lying in the basal plane.

Tem Characterization of ZnO and AIN/ZnO Thin Films Grown on Sapphire

1998 ◽  
Vol 526 ◽  
Author(s):  
K. Dovidenko ◽  
S. Oktyabrsky ◽  
A. K. Sharma ◽  
J. Narayan
Keyword(s):  
Single Crystal ◽  
Pulsed Laser Deposition ◽  
Basal Plane ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Zno Films ◽  
Threading Dislocation ◽  
Epitaxial Relationship ◽  
Spinel Layer ◽  
Plan View

AbstractThin (~ 250 nm) films of ZnO grown by pulsed laser deposition on basal plane of sapphire were studied by transmission electron microscopy (TEM). Plan-view TEM study proved the films to be single crystal with the following epitaxial relationship with the substrate: (0001)znO || (0001)sap with the 30 30° in-plane rotation - [0110]ZnO || [1210]sap. Dislocations lying mostly in basal plane of ZnO and aligned along both <:1010> and <1120> directions having b=1/3[1120] were found. ZnO films were found to have layered growth morphology contrary to columnar morphology of III-nitrides. Consequently, the threading dislocation density in ZnO films (opposing to the AIN and GaN) drops very fast with the thickness: down to 107cm-2 at ~ 250 nm. The effect of post-annealing (which caused significant improvement in electrical and optical properties) on the microstructure of ZnO films was also studied. Contrary to the atomically sharp and clean interface in the as-deposited films, the post-annealed ZnO/sapphire interface contained reacted layer of 30 - 60 A thickness. The structure of the interlayer was determined to be ZnAl2O4 (spinel). The formation of this single crystal spinel layer did not cause deterioration of the ZnO film structure or properties. We have also explored the possibilities of using ZnO as a buffer for III-nitride growth. The epitaxial AIN films were grown on top of the ZnO layer by pulsed laser deposition. Thin (20 -60 A) interfacial reaction layer (also spinel ZnAm2O4) was observed between AIN and ZnO. Formation of this interlayer is studied in conjunction with the AIN epitaxy and the characteristics of defects and interfaces.

scholarly journals Effect of neodymium doping on structural, microscopic and electrical properties of barium phosphate system

2014 ◽  
Vol 04 (02) ◽  
pp. 1450007 ◽  
Author(s):  
Shivani Suri ◽  
Vishal Singh ◽  
K. K. Bamzai
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Stoichiometric Composition ◽  
Solution Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Solution ◽  
Flower Type ◽  
Phosphate System

Neodymium-doped barium phosphate (NdBP) was prepared as single crystal by room temperature solution technique known as gel encapsulation technique. Single crystal X-ray diffraction shows that the crystal belongs to orthorhombic system. The flower type morphology was observed by scanning electron microscope (SEM) and the stoichiometric composition of the prepared crystal was observed by energy dispersive X-ray analysis (EDAX). The presence of functional group and other groups was studied by Fourier transform infrared spectroscopy (FTIR). The electrical properties of these materials like dielectric constant (ε′), dielectric loss (tanδ) and ac conductivity [ln(σac)] was studied at different temperatures ranging from 40°C to 420°C in the frequency range of 5 kHz to 1 MHz. The activation energy values decreases with increase in frequency suggesting that the conduction mechanism is because of hopping of charge carriers.

Low Defect Density Bulk AlN Substrates for High Performance Electronics and Optoelectronics

2012 ◽  
Vol 717-720 ◽  
pp. 1287-1290 ◽  
Author(s):  
Balaji Raghothamachar ◽  
Rafael Dalmau ◽  
Baxter Moody ◽  
H. Spalding Craft ◽  
Raoul Schlesser ◽  
...  
Keyword(s):  
Single Crystal ◽  
Basal Plane ◽  
High Performance ◽  
Defect Density ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Threading Dislocations ◽  
Crystalline Perfection ◽  
X Ray

Using the physical vapor transport (PVT) method, single crystal boules of AlN have been grown and wafers sliced from them have been characterized by synchrotron white beam X-ray topography (SWBXT) in conjunction with optical microscopy. X-ray topographs reveal that the wafers contain dislocations that are inhomogeneously distributed with densities varying from as low as 0 cm-2 to as high as 104 cm-2. Two types of dislocations have been identified: basal plane dislocations and threading dislocations, both having Burgers vectors of type 1/3<112-0> indicating that their origin is likely due to post-growth deformation. In some cases, the dislocations are arranged in low angle grain boundaries. However, large areas of the wafers are nearly dislocation-free and section X-ray topographs of these regions reveal the high crystalline perfection.

scholarly journals Synthesis, Growth, and Characterization of Bisglycine Hydrobromide Single Crystal

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Koteeswari Pandurangan ◽  
Sagadevan Suresh
Keyword(s):  
Single Crystal ◽  
Grown Crystal ◽  
Second Harmonic ◽  
Green Light ◽  
Etch Pits ◽  
Modes Of Vibration ◽  
Different Temperatures ◽  
Evaporation Technique ◽  
Angle Method ◽  
Unit Cell Dimensions

Single crystals of BGHB were grown by slow evaporation technique. The unit cell dimensions and space group of the grown crystals were confirmed by single crystal X-ray diffraction. The modes of vibration of the molecules and the presence of functional groups were identified using FTIR technique. The microhardness study shows that the Vickers hardness number of the crystal increases with the increase in applied load. The optical properties of the crystals were determined using UV-Visible spectroscopy. The thermal properties of the grown crystal were also determined. The refractive index was determined as 1.396 using Brewster’s angle method. The emission of green light on passing the Nd: YAG laser light confirmed the second harmonic generation property of the crystals and the SHG efficiency of the crystals was found to be higher than that of KDP. The dielectric constant and dielectric loss measurements were carried out for different temperatures and frequencies. The ac conductivity study of the crystals was also discussed. The photoconductivity studies confirm that the grown crystal has negative photoconductivity nature. The etching studies were carried out to study the formation of etch pits.

scholarly journals Pyroelectric Energy Harvesting: With Thermodynamic-Based Cycles

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Saber Mohammadi ◽  
Akram Khodayari
Keyword(s):  
Energy Harvesting ◽  
Single Crystal ◽  
Ferroelectric Materials ◽  
Temperature Variations ◽  
Thermodynamic Cycles ◽  
Sensor Applications ◽  
Different Temperatures

This work deals with energy harvesting from temperature variations using ferroelectric materials as a microgenerator. The previous researches show that direct pyroelectric energy harvesting is not effective, whereas thermodynamic-based cycles give higher energy. Also, at different temperatures some thermodynamic cycles exhibit different behaviours. In this paper pyroelectric energy harvesting using Lenoir and Ericsson thermodynamic cycles has been studied numerically and the two cycles were compared with each other. The material used is the PMN-25 PT single crystal that is a very interesting material in the framework of energy harvesting and sensor applications.

THE USE OF SHAPE-MEMORY ALLOYS FOR MECHANICAL REFRIGERATION

2009 ◽  
Vol 02 (02) ◽  
pp. 73-78 ◽  
Author(s):  
LLUÍS MAÑOSA ◽  
ANTONI PLANES ◽  
EDUARD VIVES ◽  
ERELL BONNOT ◽  
RICARDO ROMERO
Keyword(s):  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Large Temperature ◽  
Martensitic Transition ◽  
Stress Strain ◽  
Temperature Changes ◽  
Entropy Changes ◽  
Elastocaloric Effect ◽  
Different Temperatures

This letter reports on stress–strain experiments on a Cu – Zn – Al single crystal performed using a purpose-built tensile device which enables the load applied to the specimen to be controlled while elongation is continuously monitored. From the measured isothermal tensile curves, the stress-induced entropy changes are obtained at different temperatures. These data quantify the elastocaloric effect associated with the martensitic transition in shape-memory alloys. The large temperature changes estimated for this effect, suggest the possibility of using shape-memory alloys as mechanical refrigerators.

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