POLARISED TEMPERATURE DEPENDENT XANES STUDY OF SUPERCONDUCTING La2-xSrxCuO4-y UNDER- AND OVER-DOPED SINGLE CRYSTALS

2002 ◽  
Vol 16 (09) ◽  
pp. 1327-1339 ◽  
Author(s):  
C. CONCHA ◽  
J. GARCIA ◽  
J. BLASCO ◽  
K. B. GARG ◽  
R. K. SINGHAL ◽  
...  
Keyword(s):  
Phase Transition ◽  
Temperature Dependence ◽  
Single Crystals ◽  
The Other ◽  
Planar Geometry ◽  
Temperature Dependent ◽  
Characteristic Temperatures ◽  
Square Planar ◽  
Planar Systems ◽  
Made In

High resolution XANES measurements have been made at the CuK-absorption edge on two La 2-x Sr x CuO 4-y single crystals; one under-doped (x = 0.13) and the other over-doped (x = 0.19). These measurements have been made in E//ab and E//c directions at several temperatures to compare the doping, orientation and temperature dependence in their behaviour. Broadly speaking, their XANES spectra resemble the typical one from a crystal with square-planar geometry and the various fine structure features assigned to the possible transitions they arise due to, particularly in terms of the fact that the 4p band in Cu splits into 4p(π) and 4p(σ) components in these square-planar systems. However, the temperature dependence of the various features in the spectra from the two crystals appear to be opposite in nature and exhibit some characteristic temperatures at which the trend seems to reverse. All the experimental results and their implication are discussed and a possibility of phase transition of these systems at lower temperatures is hinted at.

Results of SIMS, LTPL and Temperature-Dependent Hall Effect Measurements Performed on Al-Doped α-SiC Substrates Grown by the M-PVT Method

2006 ◽  
Vol 527-529 ◽  
pp. 633-636 ◽  
Author(s):  
Sylvie Contreras ◽  
Marcin Zielinski ◽  
Leszek Konczewicz ◽  
Caroline Blanc ◽  
Sandrine Juillaguet ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Hall Effect ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Temperature Dependent ◽  
Large N ◽  
Hall Effect Measurements ◽  
Van Der Pauw ◽  
P Type ◽  
Made In

We report on investigation of p-type doped, SiC wafers grown by the Modified- Physical Vapor Transport (M-PVT) method. SIMS measurements give Al concentrations in the range 1018 to 1020 cm-3, with weak Ti concentration but large N compensation. To measure the wafers’ resistivity, carrier concentration and mobility, temperature-dependant Hall effect measurements have been made in the range 100-850 K using the Van der Pauw method. The temperature dependence of the mobility suggests higher Al concentration, and higher compensation, than estimated from SIMS. Additional LTPL measurements show no evidence of additional impurities in the range of investigation, but suggest that the additional compensation may come from an increased concentration of non-radiative centers.

Origin of ferroelectric phase transition in SbSClxI1-x mixed crystals

2014 ◽  
Vol 28 (30) ◽  
pp. 1450209 ◽  
Author(s):  
A. Audzijonis ◽  
L. Žigas ◽  
R. Sereika ◽  
R. Žaltauskas
Keyword(s):  
Phase Transition ◽  
Free Energy ◽  
Temperature Dependence ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Harmonic Approximation ◽  
Temperature Dependent ◽  
Normal Coordinate ◽  
Unit Cell Parameters ◽  
Cell Parameters

The measurements of SbSCl x I 1-x(x = 0.2) temperature dependent capacitance were carried out. The temperature of ferroelectric phase transition TC ≈340 K was measured experimentally. TC of SbSCl x I 1-x was calculated theoretically in anharmonic and harmonic approximations. TC was calculated in anharmonic approximation using temperature dependence of mean potential energy of Sb atoms as a function of the soft B1u symmetry normal coordinate along c(z)-axis. Moreover, TC was calculated in harmonic approximation using temperature dependence of vibrational thermodynamic functions (Helmholc free energy). TC dependence from unit cell parameters a, b and from mixture composition x was carried out.

Plastic Deformations in L10-Ordered Single Crystals with their c/a Ratios Less than Unity

2007 ◽  
Vol 561-565 ◽  
pp. 459-462
Author(s):  
Katsushi Tanaka ◽  
Hiromitsu Ide ◽  
Yoshinori Sumi ◽  
Kyosuke Kishida ◽  
Haruyuki Inui
Keyword(s):  
Shear Stress ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Room Temperature ◽  
The Other ◽  
Compressive Deformation ◽  
Positive Temperature ◽  
Plastic Deformations ◽  
Temperature Range ◽  
Critical Resolved Shear Stress

Compressive deformation of L10-ordered single crystals of FePd whose c/a ratio less than unity have been investigated from room temperature to 823 K. The results show that the critical resolved shear stress (CRSS) for octahedral glide of ordinary dislocations is smaller than that of super-lattice dislocations in all the temperature range investigated, that is the opposite sense to the case of Ti-56 mol% Al. The CRSS for ordinary dislocations virtually independent to the temperature. On the other hand, the CRSS for super dislocations exhibits a weak positive temperature dependence from room temperature up to 573 K and decreases in higher temperatures.

Temperature and electric field induced phase transition in [110]C-oriented 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 single crystals

CrystEngComm ◽  
2015 ◽  
Vol 17 (45) ◽  
pp. 8664-8670 ◽  
Author(s):  
Wenhui He ◽  
Qiang Li ◽  
Nengneng Luo ◽  
Yiling Zhang ◽  
Qingfeng Yan
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
Light Microscopy ◽  
Single Crystals ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Temperature Dependent ◽  
Dependent Domain

Temperature-dependent domain configurations were studied for both unpoled and poled [110]C-oriented 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 (PMN–0.37PT) single crystals by polarized light microscopy (PLM).

Structure Characteristics of Cubic and Orthorhombic Phases of High Density Scintillator Pbf2 from 4.2–300 K

1994 ◽  
Vol 348 ◽  
Author(s):  
Ivan Shmyt'ko ◽  
I.B. Savchenko ◽  
N.V. Klassen ◽  
B.Sh. Bagautdinov ◽  
G.A. Emel'chenko ◽  
...  
Keyword(s):  
Phase Transition ◽  
Plastic Deformation ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Room Temperature ◽  
Cell Parameter ◽  
Structure Characteristics ◽  
Pseudocubic Phase ◽  
Bulk Single Crystals ◽  
Structural Aspects

ABSTRACTAn anomaly of the temperature dependence of the unit cell parameter has been observed for β–PbF2 single crystals at 200 K that is interpreted as a phase transition to a pseudocubic lattice. Such a pseudocubic phase is observable at room temperature after uniaxial plastic deformation of the bulk single crystals. The structural aspects of the β→α transition have been established. The as-grown crystals of α–PbF2 phase are shown to undergo a phase transition at 100 K.

Azido{2-[(tri-2-pyridylmethyl)iminomethyl]phenolato}nickel(II)

2007 ◽  
Vol 63 (11) ◽  
pp. m2812-m2812 ◽  
Author(s):  
Lai-Jin Tian ◽  
Hong-Jun Yang ◽  
Zhong-Hai Ni
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Sodium Azide ◽  
Title Compound ◽  
Methanol Solution ◽  
The Other ◽  
Planar Geometry ◽  
Square Planar ◽  
Azide Ligand

The title compound, [Ni(C23H17N4O)(N3)], was obtained by the reaction of the Schiff base ligand 2-[(tri-2-pyridylmethyl)iminomethyl]phenol with sodium azide and nickel(II) perchlorate in methanol solution. The NiII atom is four-coordinated by the phenolate O, the imine N and a pyridine N atom of the Schiff base ligand, and by the terminal N atom of an azide ligand, forming a square-planar geometry. The other two pyridyl rings are oriented at an angle of 72.29 (11)° to each other.

Magneto-Optical Study of Martensitic Transition in Ni45Mn36.7In13.3Co5 (at. %) Single Crystals

2015 ◽  
Vol 233-234 ◽  
pp. 225-228 ◽  
Author(s):  
Elena Gan’shina ◽  
Andrey Novikov ◽  
Volodymyr Chernenko ◽  
J. Barandiaran ◽  
Eduard Cesari ◽  
...  
Keyword(s):  
Single Crystals ◽  
Kerr Effect ◽  
Cold Water ◽  
Czochralski Method ◽  
The Other ◽  
Martensitic Transition ◽  
Optical Study ◽  
Scanning Calorimetry ◽  
Characteristic Temperatures ◽  
Annealing Conditions

Transverse Kerr effect (TKE) was used to study magneto-optical (MO) properties of Ni45Mn36.7In13.3Co5 (at.%) single crystals. A single crystalline ingot of such composition was grown by the Czochralski method. One series of samples was quenched into cold water (WQ) and the other series after quenching was heated at 770 K for 20 min and slowly cooled to assure a complete atomic order (SC). Accordingly to differential scanning calorimetry (DSC), magnetic and magneto-optical (MO) measurements, WQ samples exhibit well-defined martensitic transition (MT), but the SC samples do not show MT. It is found that TKE for WQ samples shows the following features (i) MO signal is well pronounced far below the martensitic transition in spite of a weak magnetization of martensitic phase; (ii) the characteristic temperatures of martensitic transition differ from those for the bulk and depend on annealing conditions; (iii) MO spectra profile do not change significantly during the martensitic transition and is similar but not identical with that for Ni50Mn35In15 thin films and Ni43.7Mn43.6In12.7 ribbons measured before; (iv) MO signal is anisotropic.

Temperature dependence of piezoelectric properties of 0.67 Pb(Mg1/3Nb2/3)O3–0.33 PbTiO3 single crystals

2003 ◽  
Vol 18 (2) ◽  
pp. 537-541 ◽  
Author(s):  
Ping-chu Wang ◽  
Xiao-ming Pan ◽  
Dong-lin Li ◽  
Yuan-wei Song ◽  
Hao-su Luo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Phase Transition Temperature ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Device Design ◽  
Temperature Range ◽  
Approach Zero

Piezoelectric properties k33 and d33 of 0.67 Pb(Mg1/3Nb2/3)O3–0.33 PbTiO3 single crystals grown by a modified Bridgman method were measured in the temperature range of 20–150 °C. Recoverability of the properties after the samples were heated to 110 °C, above the ferroelectric–ferroelectric (F–F) phase transition temperature of the composition, was found. From 20 to approximately 80 °C, k33 increases slightly, while d33 is almost doubled. Between approximately 90 and 100 °C, k33 decreases sharply to roughly a level of PZT-5 ceramics and d33 decreases to about 700 pC/N. They increase again with further increase of temperature; at 140 °C they attain 0.74 and approximately 1300 pC/N, respectively, and then decrease quickly and approach zero at about 150 °C. When heating to 110 °C followed by cooling to room temperature, the property decay is small. After more than one dozen heating–cooling cycles, k33 and d33 tend to be stable at 0.89 and approximately 1220 pC/N, respectively. The results might be helpful for device design and applications of PMN–PT single crystals.

Pressure- and temperature-dependent inelastic neutron scattering study of the phase transition and phonon lattice dynamics in para-terphenyl

2021 ◽  
Author(s):  
Qingan Cai ◽  
Michael McIntire ◽  
Luke L. Daemen ◽  
Chen Li ◽  
Eric L. Chronister
Keyword(s):  
Phase Transition ◽  
Neutron Scattering ◽  
Temperature Dependence ◽  
Lattice Dynamics ◽  
Inelastic Neutron Scattering ◽  
Ambient Pressure ◽  
Inelastic Neutron ◽  
Temperature Dependent ◽  
Scattering Study ◽  
Neutron Scattering Study

Inelastic neutron scattering has been performed on para-terphenyl at temperatures from 10 to 200 K and under pressures from the ambient pressure to 1.51 kbar. The temperature dependence of phonons,...

scholarly journals Bis{2-methoxy-6-[(E)-(4-methylbenzyl)iminomethyl]phenolato}palladium(II) chloroform monosolvate

2014 ◽  
Vol 70 (8) ◽  
pp. m289-m290 ◽  
Author(s):  
Hadariah Bahron ◽  
Amalina Mohd Tajuddin ◽  
Wan Nazihah Wan Ibrahim ◽  
Suchada Chantrapromma ◽  
Hoong-Kun Fun
Keyword(s):  
Solvent Molecule ◽  
Title Complex ◽  
The Other ◽  
Planar Geometry ◽  
Inversion Center ◽  
Complex Molecules ◽  
Square Planar ◽  
Solvent Molecules ◽  
Cl Atom ◽  
Full Occupancy

In the title complex, [Pd(C16H16NO2)2]·CHCl3, the PdIIcation lies on an inversion center. One Cl atom of the CHCl3solvent molecule lies on a twofold axis and the C—H group is disordered with equal occupancies about this axis with the other Cl atom in a general position with full occupancy. The PdIIcation is four-coordinate and adopts a square-planar geometryviacoordination of the imine N and phenolic O atoms of the two bidentate Schiff base anions. The N and O atoms of these ligands are mutuallytrans. The plane of the benzene ring makes a dihedral angle of 73.52 (10)° with that of the methoxyphenolate ring. In the crystal, molecules of the PdIIcomplex are arranged into sheets parallel to theacplane, and the chloroform solvent molecules are located in the interstitial areas between the complex molecules. Weak intermolecular C—H...O and C—H...π interactions stabilize the packing.

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