Raman spectroscopy as a key method to distinguish the ferroelectric orthorhombic phase in thin ZrO 2 ‐based films

2022 ◽  
Author(s):  
Monica Materano ◽  
Peter Reinig ◽  
Alfred Kersch ◽  
Maxim Popov ◽  
Marco Deluca ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Orthorhombic Phase

Piezoelectric (Na0.5K0.5)NbO3-SrTiO3Ceramics in the Tetragonal-Orthorhombic Phase Boundary Studied by Raman Spectroscopy

2007 ◽  
Vol 347 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Jun Kano ◽  
Keita Sasanuma ◽  
Shinya Tsukada ◽  
Seiji Kojima ◽  
Ruiping Wang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Phase Boundary ◽  
Orthorhombic Phase

CHARACTERIZATION OF POTASSIUM DOPED GdBa2Cu3O7−δ USING RAMAN SPECTROSCOPY AND X-RAY DIFFRACTION

1995 ◽  
Vol 09 (26n27) ◽  
pp. 1739-1752
Author(s):  
PREETHI CICILY THOMAS ◽  
MANOJ KUMAR K. ◽  
V. UNNIKRISHNAN NAYAR ◽  
VIDYALAL V. ◽  
C.P.G. VALLABHAN
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Tetragonal Phase ◽  
Orthorhombic Phase ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Xrd Patterns

Potassium doped and undoped GdBa 2 Cu 3 O 7−δ have been prepared and superconducting transition temperatures between 92 K and 100 K have been determined from resistivity measurements. Raman spectra of doped and undoped samples are identical and they contain bands corresponding to both the superconducting orthorhombic phase and nonsuperconducting tetragonal phase. XRD patterns also reveal both the phases. Raman spectra recorded at 92 K of undoped GdBa 2 Cu 3 O 7−δ and doped GdBa 2 Cu 3 O 7−δ with weight percentages 0.75, 1.00, 1.25 and 1.50 of K shows a softening of the band at 338 cm−1.

Twin boundary structure of a Y-Ba-Cu-O superconductor

1989 ◽  
Vol 47 ◽  
pp. 168-169
Author(s):  
Yimei Zhu ◽  
Masaki Suenaga ◽  
R. L. Sabatini ◽  
Youwen Xu
Keyword(s):  
Twin Boundary ◽  
Fine Particles ◽  
Imaging Techniques ◽  
Fine Powder ◽  
Orthorhombic Phase ◽  
Boundary Structure ◽  
Crystallographic Axis ◽  
System A ◽  
High Resolution Structure ◽  
Electron Microscopes

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.

Structure of a new orthorhombic phase in NiTi: Mn shape memory alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 1000-1001
Author(s):  
Jenö Beyer ◽  
Lajos Tóth
Keyword(s):  
Martensitic Transformation ◽  
Structural Changes ◽  
High Vacuum ◽  
Intermetallic Phase ◽  
Orthorhombic Phase ◽  
Transformation Process ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Crystallographic Structures ◽  
Ternary Additions

The structural changes during reversible martensitic transformation of near-equiatomic NiTi alloys can best be studied in TEM at around room temperature. Ternary additions like Mn offer this possibility by suppressing the Ms temperature below RT. Besides the stable intermetallic phases (Ti2Ni, TiNi, TiNi3) several metastable phases with various crystallographic structures (rhombohedral, hexagonal, monoclinic, cubic) have also been reported to precipitate due to suitable annealing procedures.TiNi:Mn samples with 0.9 and 1.3 at% Mn were arc melted in argon atmosphere and homogenized at 948 °C for 72 hours in high vacuum in an infrared furnace. After spark cutting slices of 0.2 mm, TEM specimens were prepared by electrochemical polishing with the twin-jet technique in methanol - perchloric acid electrolyte. The TEM study was carried out in a JEOL 200 CX analytical electron microscope.In this paper a new intermetallic phase is reported which has been observed in both samples by TEM during the martensitic transformation process.

Microdomains in BaFeO3-y (0.35 < y < 0.50)

1990 ◽  
Vol 48 (4) ◽  
pp. 780-781
Author(s):  
M. Vallet-Regí ◽  
M. Parras ◽  
J.M. González-Calbet ◽  
J.C. Grenier
Keyword(s):  
Electron Diffraction ◽  
Chemical Analysis ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Total Iron ◽  
Zone Axis ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compositional Variations

BaFeO3-y compositions (0.35<y<0.50) have been investigated by means of electron diffraction and microscopy to resolve contradictory results from powder X-ray diffraction data.The samples were obtained by annealing BaFeO2.56 for 48 h. in the temperature range from 980°C to 1050°C . Total iron and barium in the samples were determined using chemical analysis and gravimetric methods, respectively.In the BaFeO3-y system, according to the electron diffraction and microscopy results, the nonstoichiometry is accommodated in different ways as a function of the composition (y):In the domain between BaFeO2.5+δBaFeO2.54, compositional variations are accommodated through the formation of microdomains. Fig. la shows the ED pattern of the BaFeO2.52 material along thezone axis. The corresponding electron micrograph is seen in Fig. 1b. Several domains corresponding to the monoclinic BaFeO2.50 phase, intergrow with domains of the orthorhombic phase. According to that, the ED pattern of Fig. 1a, can be interpreted as formed by the superposition of three types of diffraction maxima : Very strong spots corresponding to a cubic perovskite, a set of maxima due to the superposition of three domains of the monoclinic phase along [100]m and a series of maxima corresponding to three domains corresponding to the orthorhombic phase along the [100]o.

Raman spectroscopy and X-ray diffraction of lithium niobate at temperatures up to 1300○-4.80pt○C

2005 ◽  
Vol 126 ◽  
pp. 101-105 ◽  
Author(s):  
B. Moulin ◽  
L. Hennet ◽  
D. Thiaudière ◽  
P. Melin ◽  
P. Simon
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
X Ray Diffraction ◽  
X Ray

Raman spectroscopy using a gas laser

1965 ◽  
Vol 26 (11) ◽  
pp. 620-626 ◽  
Author(s):  
J.P. Russell
Keyword(s):  
Raman Spectroscopy ◽  
Gas Laser
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