Impedanzmessungen an Tetraiodomercuraten/Impedance Spectroscopy of Tetraiodomercurates

1992 ◽  
Vol 47 (1) ◽  
pp. 17-21 ◽  
Author(s):  
K. Brodersen ◽  
H. Göhr ◽  
J. Schrenk
Keyword(s):  
Phase Transitions ◽  
Impedance Spectroscopy ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Double Layer ◽  
Powder Sample ◽  
Ionic Mobilities

As thermochromic compounds, tetraiodomercurates show phase transitions, which have been investigated by impedance spectroscopy. In the case of Ag2HgI4 and Cu2HgI4 we found clear changes of conductivity not present with HgI2. In all cases the main resistance is caused by the grain boundaries between the single crystals of the powder sample. Also diffusion in the double layer in front of the surface of the electrodes influences the spectra. Single crystal measurements of Hgl, show the different ionic mobilities along the various crystallographic directions.

The observation of defects on (100) CdTe surfaces by chemical etching

1992 ◽  
Vol 50 (2) ◽  
pp. 1424-1425
Author(s):  
M.E. Lee
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Chemical Etching ◽  
Crystalline Perfection ◽  
Crystalline Defects ◽  
High Incidence ◽  
Crystallographic Defects ◽  
Cdznte Substrates ◽  
Device Technology

The crystalline perfection of bulk CdTe substrates plays an important role in their use in infrared device technology. The application of chemical etchants to determine crystal polarity or the density and distribution of crystallographic defects in (100) CdTe is not well understood. The lack of data on (100) CdTe surfaces is a result of the apparent difficulty in growing (100) CdTe single crystal substrates which is caused by a high incidence of twinning. Many etchants have been reported to predict polarity on one or both (111) CdTe planes but are considered to be unsuitable as defect etchants. An etchant reported recently has been considered to be a true defect etchant for CdTe, MCT and CdZnTe substrates. This etchant has been reported to reveal crystalline defects such as dislocations, grain boundaries and inclusions in (110) and (111) CdTe. In this study the effect of this new etchant on (100) CdTe surfaces is investigated.The single crystals used in this study were (100) CdTe as-cut slices (1mm thickness) from Bridgman-grown ingots.

scholarly journals Ferroelectricity and Phase Transitions in Pyridinium Periodate Single Crystal

2000 ◽  
Vol 55 (11-12) ◽  
pp. 891-894 ◽  
Author(s):  
Z. Czapla ◽  
S. Dacko ◽  
B. Kosturek
Keyword(s):  
Phase Transitions ◽  
Physical Properties ◽  
Single Crystal ◽  
Single Crystals ◽  
Phase Ii ◽  
Ferroelectric Phase ◽  
Hysteresis Loops ◽  
Electric Permittivity ◽  
Phase Ii And Iii ◽  
Three Phases

Abstract Single crystals of pyridinium periodate were grown, and their physical properties were studied. Anomalies of the electric permittivity and birefringence were observed at TC1 = 321 K and TC2 = 211 K. These observations gave evidences for the existence of three phases denoted as I, II, and III. Hysteresis loops were observed both in phase II and III. Pyroelectric measurements showed two anomalies at TC1 and TC2 . The anomaly at TC1 is related to the transition between a para-and ferroelectric phase, and the anomaly at T cl to the transition between two ferroelectric phases.

scholarly journals Magnetocaloric properties of the single crystal Mn0.99Fe0.01As

2019 ◽  
Vol 55 (1) ◽  
pp. 118-124
Author(s):  
G. A. Govor ◽  
A. O. Larin ◽  
V. I. Mitsiuk ◽  
G. S. Rimskiy ◽  
T. M. Tkachenkа
Keyword(s):  
Magnetic Field ◽  
Crystal Structure ◽  
Phase Transition ◽  
Phase Transitions ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Single Crystals ◽  
Calculation Method ◽  
Magnetostructural Transition ◽  
Magnetocaloric Properties

The Stockbargard – Bridgman method yielded single crystals Mn0.99Fe0.01As. The effect of an external magnetic field with an intensity of up to 10 T on phase transitions in the single crystal Mn0.99Fe0.01As is studied. It is established that the magnetostructural phase transition in Mn0.99Fe0.01As is accompanied by a change in the entropy ΔSm, which is due to the transformation of the crystal structure. At temperatures above the temperature of the magnetostructural transition Tu = 290 K, the existence of an unstable magnetic structure is obtained. The magnetocaloric characteristics of the material under study are determined by an indirect calculation method based on the Maxwell thermodynamic relations and the Clapeyron – Clausius equation.

Structure of tetrakis(dimethylamino)ethene (TDAE) at low temperatures

1995 ◽  
Vol 210 (7) ◽  
Author(s):  
J. Bruckmann ◽  
C. Krüger ◽  
H. Borrmann ◽  
A. Simon ◽  
H. Bock
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Low Temperatures ◽  
Structure Refinement ◽  
Static Disorder ◽  
Structural Details ◽  
Different Temperatures

AbstractThe single crystal structure of TDAE was redetermined at different temperatures. Phase transitions are observed by warming the samples from low temperatures but never by cooling. Due to this special behavior it was possible to cool single crystals to 90 K. The data collected from such supercooled crystals resulted in a more precise and reliable structure refinement. Interesting structural details of the sterically overcrowded molecule are elucidated. The temperature dependence of the distortions of the nonplanar dimethylamino groups indicates dynamic behavior rather than static disorder.

EPR Studies of VO2+ in Ba(ClO4) 2 ・3H2O Single Crystals

1997 ◽  
Vol 52 (12) ◽  
pp. 849-854 ◽  
Author(s):  
Metin Yavuz ◽  
Hüseyin Kalkan ◽  
Ahmet Bulut ◽  
Şehriman Atalay ◽  
Emin Öztekin
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystal ◽  
Single Crystals ◽  
Axial Symmetry ◽  
Powder Sample ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Vanadyl Ion ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

The results of an electron paramagnetic resonance (EPR) study of vanadyl ion VO2+ doped in single crystals of Ba(ClO4)2 - 3 H2O are reported. The spectra indicated the presence of two substitutional and interstitial sites depending on the orientation. The spin-Hamiltonian parameters were determined from single crystal and powder EPR data. These parameters were found to be axial symmetric for the powder sample, whereas they showed deviations from axial symmetry for the single crystal

Analysis of defect formation in Nb-doped SrTiO3 by impedance spectroscopy

2001 ◽  
Vol 16 (1) ◽  
pp. 192-196 ◽  
Author(s):  
Seong-Ho Kim ◽  
Jung-Ho Moon ◽  
Jae-Hwan Park ◽  
Jae-Gwan Park ◽  
Yoonho Kim
Keyword(s):  
Activation Energy ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Thermal Activation ◽  
Oxygen Vacancies ◽  
Defect Formation ◽  
Activation Energies ◽  
Single Grain

The thermal activation energies for conduction of Nb-doped SrTiO3 grains and grain boundaries have been investigated by impedance spectroscopy. First, to observe the effect of electrode/SrTiO3 bulk interface, the varied impedances of SrTiO3 single crystal were measured with temperatures. The activation energy of an electrode/bulk interface was determined to be 1.3 eV, whereas that of bulk was 0.8 eV. When the impedances of Nb-doped SrTiO3 ceramics were measured, it was suggested that the more precise impedance values of a single grain and a single grain to grain junction be obtained using a microelectrode method. The activation energies for a grain, a grain boundary, and an electrode/bulk interface were determined to be about 0.8, 1.3, and 1.5 eV, respectively. From these measured results, it was suggested that the activation energy, 0.8 eV, measured in grain was originated from oxygen vacancies and the activation energy, 1.3 eV, in grain boundary was from strontium vacancies.

THE EFFECTS OF GRAIN BOUNDARIES ON THE PLASTIC DEFORMATION OF ZINC CRYSTALS

1957 ◽  
Vol 35 (1) ◽  
pp. 38-47 ◽  
Author(s):  
G. B. Craig ◽  
B. Chalmers
Keyword(s):  
Plastic Deformation ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Basal Plane ◽  
Basal Slip ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

The tensile plastic deformation of single-crystal and tricrystal specimens of zinc was investigated by analysis of the external change in shape of the specimens, and of the changes in X-ray diffraction patterns. It was demonstrated that the single crystals deformed by slip on the basal plane, but pyramidal as well as basal slip occurred in specimens containing grain boundaries.

Relaxor Single-Crystal Plates with Nano-Size Ferroelectric Domains Applying to Ultrasonic Prove for Medical Uses

2016 ◽  
Vol 102 ◽  
pp. 57-64
Author(s):  
Toshio Ogawa ◽  
Taiki Ikegaya
Keyword(s):  
Bulk Modulus ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Domain Alignment

Sound velocities were measured in relaxor single-crystal plates, included in piezoelectric transducers for medical uses, using an ultrasonic precision thickness gauge with high-frequency pulse generation. The velocities were compared with the ones of piezoelectric ceramics in order to clarify characteristics of the single crystals. Estimating the difference in the sound velocities and elastic constants in the single crystals and ceramics, it was possible to evaluate effects of domain and grain boundaries on elastic constants. Existence of domain boundaries in single crystal affected the decrease in Young’s modulus, rigidity, Poisson’s ratio and bulk modulus. While existence of grain boundaries affected the decrease in Young’s modulus and rigidity, Poisson’s ratio and bulk modulus increased. It was thought these phinomina come from domain alignment by DC poling, and both the boundaries act as to absorb mechanical stress by defects due to the boundaries. In addition, the origin of piezoelectricity in single crystals is caused by low bulk modulus and Poisson’s ratio, and high Young’s modulus and rigidity in comparison with ceramics. On the contrary, the origin of piezoelectricity in ceramics is caused by high Poisson’s ratio by high bulk modulus, and furthermore, low Young’s modulus and rigidity due to domain alignment.

A microcontact impedance study on NASICON-type Li1+xAlxTi2−x(PO4)3(0 ≤ x ≤ 0.5) single crystals

2016 ◽  
Vol 4 (4) ◽  
pp. 1506-1513 ◽  
Author(s):  
D. Rettenwander ◽  
A. Welzl ◽  
S. Pristat ◽  
F. Tietz ◽  
S. Taibl ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Solid Electrolytes ◽  
Bulk Conductivity ◽  
Impedance Study ◽  
Nasicon Type ◽  
Microstructural Effects

We successfully demonstrated the applicability of microcontact impedance spectroscopy (MC IS) on Li+conducting solid electrolytes and measured the Li+bulk conductivity (σb) of LiTi2(PO4)3(LTP) and Li1+xAlxTi2−x(PO4)3(LATP) single crystals independent of microstructural effects (e.g., grain boundaries, pores, and density).

Mounting an individual submicrometer sized single crystal

1996 ◽  
Vol 211 (6) ◽  
Author(s):  
R. B. Neder ◽  
M. Burghammer ◽  
Th. Grasl ◽  
H. Schulz
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Single Crystals ◽  
High Vacuum ◽  
Nanometer Resolution ◽  
Micro Manipulator ◽  
Scanning Electron

AbstractWe developed a new micro manipulator for mounting individual sub-micrometer sized single crystals within a scanning electron microscope. The translations are realized via a commercially available piezomicroscope, adapted for high vacuum usage and realize nanometer resolution. With this novel instrument it is routinely possible to mount individual single crystals with sizes down to 0.1

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