High-accuracy polarimetric studies on lead germinate single crystals

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Mykola Shopa ◽  
Nazar Ftomyn ◽  
Yaroslav Shopa

A high-accuracy polarimetric technique has been used for the characterization of a lead germanate ferroelectric single crystal. The measurement results of the linear and circular birefringence in the [010] direction at a wavelength of 633 nm under the influence of an electric field are presented. Gyration–electric field hysteresis loops at alternative crystal positions in the polarization system have been used to determine the ellipticity of the eigenwaves. A temperature dependence of the gyration tensor component g 11 in the temperature range of 300–450 K was found.

2003 ◽  
Vol 784 ◽  
Author(s):  
A. K. Tagantsev ◽  
P. Muralt ◽  
J. Fousek

ABSTRACTA simple theory for the shape of the piezoelectric hysteresis loops (piezoelectric coefficient d vs. applied electric field E) is developed for the case of non-ferroelelastic 180° switching in ferroelectrics. The theory provides explanations for specific features of piezoelectric hysteresis loops, which have been observed in single crystals, thin films and in ceramics in particular. The piezoelectric coefficient may show a “hump”, i.e. when E decreases from the tip of the loop down to zero, d passes through a maximum, and a “nose”, i.e. a self-crossing of the loop close to its tips. The theory also explains the difference in the coercive fields seen in the polarization and piezoelectric loops.


1988 ◽  
Vol 144 ◽  
Author(s):  
K. C. Garrison ◽  
C. J. Palmstrøm ◽  
R. A. Bartynski

ABSTRACTWe have demonstrated growth of high quality single crystal CoGa films on Ga1−xAlxAs. These films were fabricated in-situ by codeposition of Co and Ga on MBE grown Ga1−xAlxAs(100) surfaces. The elemental composition of the films was determined using Rutherford Backscattering (RBS) and in-situ Auger analysis. The structural quality of the films' surfaces was studied using RHEED (during deposition) and LEED (post deposition). RBS channeling was used to determine the bulk crystalline quality of these films.For ∼500 Å CoGa films grown at ∼450°C substrate temperature, channeling data showed good quality epitaxial single crystals [χmin ∼7%] with minimal dechanneling at the interface.


Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2451
Author(s):  
Galina Kuz’micheva ◽  
Irina Kaurova

Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions.


1986 ◽  
Vol 41 (1-2) ◽  
pp. 95-98 ◽  
Author(s):  
K.-H. Ebeling ◽  
R. Eder ◽  
E. Hagn ◽  
E. Zech ◽  
M. Deicher

The techniques of quadrupole-interaction nuclear-orientation and quadrupole-interaction-resolvedNMR on oriented nuclei were applied to radioactive 111In (T1/2 = 2.8 d), 198Au(T1/2= 2.7 d) and 199Au (T1/2 = 3.1 d), mass-separator-implanted into single crystals of hep Coand hep Gd. For 111InGd the quadrupole interaction was observed via the broadening of theresonance and the dependence of the effective quadrupole interaction on the angle θbetween thec-axis of the single crystal and the direction of magnetization. For 198AuGd the large electric fieldgradient known from the literature could not be confirmed. For 198AuCo and 199AuCo thequadrupole substructure has been resolved, and the electric field gradient of Au in hep Co was determined to be -0.84(4) x 1017V/cm2. The magnetic hyperfine fields of Au in hep and fee Codiffer by about 20%. These experiments have shown that hep Co may be a good host matrix forthe determination of the quadrupole interaction of heavy radioactive nuclei with resonanceprecision.


2008 ◽  
Vol 23 (12) ◽  
pp. 3387-3395 ◽  
Author(s):  
F. Fang ◽  
W. Yang ◽  
F.C. Zhang ◽  
H. Qing

In situ observation of the electrically induced crack growth and domain-structure evolution is carried out for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3)O3–28% PbTiO3 (PMN–PT 72/28) ferroelectric single crystals under static (poling) and alternating electric fields. On the same poling electric field, domains are in the stable engineered domain state where four equivalent polarization variants coexist for [100]-oriented single crystal, while parallel lines representing the 71° domain boundaries appear for [101]-oriented one. Under the same cyclic electric field, the [100]-oriented single crystal shows much higher crack propagation resistance than that of a [101]-oriented crystal. Apart from the material aspects, such as crystallographic fracture anisotropy and non-180° domain boundary structure, crack boundary condition plays an important role in determining the crack propagation behavior.


2000 ◽  
Vol 55 (11-12) ◽  
pp. 891-894 ◽  
Author(s):  
Z. Czapla ◽  
S. Dacko ◽  
B. Kosturek

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.


2008 ◽  
Vol 63 (5) ◽  
pp. 525-529 ◽  
Author(s):  
Olaf Reckeweg ◽  
Jesse Reiherzer ◽  
Armin Schulz ◽  
Francis J. DiSalvo

Pale grey-blue, transparent single crystals of Ba2[BN2]Cl (I4132 (no. 214), a = 1462.88(1) pm, Z = 24) are obtained by the reaction of Ba, BaCl2, BN and NaN3 in arc-welded Ta ampoules at 1200 K. The crystal structure was determined by single crystal X-ray structure analysis. The Raman and IR spectra of the title compound show the expected fundamental frequencies (νs = 1038; νas = 1969 and 2087; δ = 616 / 636 cm−1) for a nitridoborate unit with D∞h symmetry. The [N-B-N] structure obtained by X-ray single crystal structure determination corroborates this finding within the standard deviations of the measurement with d(B-N) = 132.3(8) pm and ∡ (N-B-N) = 178.5(13)°. Our results compare well to the data reported for cubic and orthorhombic Ba3[BN2]2 as well as to the isotypic compound Ba2[BN2]Br.


2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542025 ◽  
Author(s):  
L. P. Cao ◽  
L. Q. Pan ◽  
W. M. Li ◽  
X. C. Wang ◽  
Q. Q. Liu ◽  
...  

Single crystal [Formula: see text] was prepared under high pressure and high temperature. Single crystal X-ray diffraction (XRD) result shows a cubic perovskite structure. The magnetic and resistivity measurement results indicate that [Formula: see text] is a paramagnetic semiconductor.


2013 ◽  
Vol 53 (5) ◽  
pp. 053005 ◽  
Author(s):  
E. Viezzer ◽  
T. Pütterich ◽  
G.D. Conway ◽  
R. Dux ◽  
T. Happel ◽  
...  

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