STRUCTURAL ASPECTS OF KMg1/3Nb2/3PO5 (KMNP), A KTP ANALOGUE — RAMAN AND FTIR SPECTROSCOPIC STUDY

2001 ◽  
Vol 10 (03) ◽  
pp. 345-353 ◽  
Author(s):  
M. J. BUSHIRI ◽  
V. U. NAYAR
Keyword(s):  
Phase Transition ◽  
Spectroscopic Study ◽  
Raman Spectra ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Ftir Spectra ◽  
Ktp Crystal ◽  
Structural Aspects

Raman and FTIR spectra of KMg1/3Nb2/3PO5 (KMNP) crystal are recorded. The observed bands are assigned mainly in terms of vibrations of NbO6 octahedra and PO4 tetrahedra. The NbO6 octahedra in the crystal are distorted. Corner shared octahedra are present in the KMNP structure. The intense ν1 band at 890 cm-1 in the Raman spectra indicates an ordering in the crystal. The TiO6 octahedra in KTP crystal are more distorted than those of NbO6 octahedra in KMNP. The presence of Mg ions disrupts Nb–O–Nb chains leading to a distortion of NbO6 octahedra different from that of TiO6 . The PO4 tetrahedra in the crystal are linearly distorted. No structural phase transition is observed in the crystal when temperature is lowered to 77 K.

scholarly journals Manifestation of magnetoelastic interactions in Raman spectra of HoxNd1−xFe3(BO3)4 crystals

2018 ◽  
Vol 08 (02) ◽  
pp. 1850011 ◽  
Author(s):  
A. S. Krylov ◽  
S. N. Sofronova ◽  
I. A. Gudim ◽  
S. N. Krylova ◽  
Rajesh Kumar ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectra ◽  
Structural Phase Transition ◽  
Solid Solutions ◽  
Order Parameter ◽  
Soft Mode ◽  
Magnetic Phase ◽  
Structural Phase ◽  
Exchange Interactions ◽  
Magnetoelastic Interaction

Raman spectra of Ho[Formula: see text]NdxFe(BO3)4 ([Formula: see text], 0.75, 0.5, 0.25) have been studied in temperature range 10–400[Formula: see text]K. Two compositions ([Formula: see text], [Formula: see text]) demonstrate structural phase transition with soft mode restoration. The addition of Nd atoms increases interatomic spacing and decreases the temperature of structural phase transition. The solid solutions ([Formula: see text], 0.5, 0.25) demonstrate the emergence of the peaks corresponding to magnetoelastic interaction below Néel temperature. The order parameter of the magnetic phase transition has been determined. The equal concentrations of holmium and neodymium atoms prevent magnon soft modes condensation caused by exchange interactions in Fe–O–Fe chains are observed. Calculations confirm the data obtained in the experiment.

High-pressure spectroscopic study of silver azide

RSC Advances ◽  
2016 ◽  
Vol 6 (85) ◽  
pp. 82270-82276 ◽  
Author(s):  
Dongmei Li ◽  
Peifen Zhu ◽  
Yanju Wang ◽  
Bingbing Liu ◽  
Junru Jiang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Spectroscopic Study ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Silver Azide

The pressure-induced structural phase transition and evolution of N3− in AgN3 are revealed by spectroscopic study.

Study of Raman spectra and structural phase transition in the system Ba2Bi4−xLaxTi5O18

1996 ◽  
Vol 218 (1-2) ◽  
pp. 91 ◽  
Author(s):  
Jianjun Liu ◽  
Chunxiao Gao ◽  
Guangtian Zou ◽  
Yanrong Jin
Keyword(s):  
Phase Transition ◽  
Raman Spectra ◽  
Structural Phase Transition ◽  
Structural Phase

High Pressure Structural Phase Transition and Elastic Properties of MgX (X = S, Se, Te) Semiconducting Compounds

2006 ◽  
Vol 987 ◽  
Author(s):  
Dinesh Varshney ◽  
Netram Kaurav ◽  
Kamal Kumar Choudhary ◽  
R. Kinge ◽  
R. K. Singh
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Repulsive Interaction ◽  
Interionic Interaction ◽  
Phase Transition Pressure ◽  
Cscl Type ◽  
Semiconducting Compounds ◽  
Structural Aspects ◽  
Vdw Interaction

AbstractPressure-induced structural aspects of NaCl-type (B1) to CsCl-type (B2) structure in MgX [X = S, Se, Te] semiconductors are presented. An effective interionic interaction potential (EIOP) with long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach is developed. Particular attention is devoted to evaluate the vdW coefficients following the variational method, as both the cation and the anion are polarizable. Our result on vast volume discontinuity in pressure volume phase diagram identifies the structural phase transition from B1 to B2 structure. The estimated value of the phase transition pressure (Pt) is consistent with results previously published. The variations of elastic constants with pressure follow a systematic trend identical to that observed in others compounds of NaCl type structure family.

scholarly journals Raman Spectra and Structural Phase Transition in Pr3Sb5O12Crystal

2015 ◽  
Vol 486 (1) ◽  
pp. 86-90
Author(s):  
Abdumalik Hojiboev ◽  
Aleksandr Oreshonkov ◽  
Maksud Umarov ◽  
Alexander Vtyurin
Keyword(s):  
Phase Transition ◽  
Raman Spectra ◽  
Structural Phase Transition ◽  
Structural Phase
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