Acoustic Properties of Ho2Si2O7 Single Crystal Investigated by Brillouin Light Scattering

2012 ◽  
Vol 510-511 ◽  
pp. 143-147
Author(s):  
Ghulam Shabbir ◽  
Asghari Maqsood ◽  
Izhar-ul-Haq
Keyword(s):  
Light Scattering ◽  
Elastic Constant ◽  
Single Crystal ◽  
Room Temperature ◽  
Acoustic Properties ◽  
Temperature Dependent ◽  
Hypersonic Velocity ◽  
Brillouin Light Scattering ◽  
Dependent Behavior ◽  
Small Dispersion

Micro-Brillouin light scattering experiments were performed on flux grown D-type (monoclinic, P21/c) Ho2Si2O7 single crystal from room temperature to 850 K. Both the hypersonic velocity (VLA) and related elastic constant (c33) of the longitudinal acoustic phonons propagating along 001-direction showed a small dispersion at T565 K whereas the same could not be observed clearly in attenuation/damping. The overall temperature dependent behavior of elastic constant and hypersonic velocity was attributed to the lattice anharmonicity of the crystal in the investigated temperature range.

Temperature-dependent spin-wave behavior in Co/CoO bilayers studied by Brillouin light scattering

2000 ◽  
Vol 62 (10) ◽  
pp. 6429-6436 ◽  
Author(s):  
A. Ercole ◽  
W. Lew ◽  
G. Lauhoff ◽  
E. Kernohan ◽  
J. Lee ◽  
...  
Keyword(s):  
Light Scattering ◽  
Spin Wave ◽  
Temperature Dependent ◽  
Brillouin Light Scattering

scholarly journals Brillouin Light Scattering Study of Microscopic Structure and Dynamics in Pyrrolidinium Based Ionic Liquids

2020 ◽  
Author(s):  
Supti Das ◽  
Dhanya Radhakrishnan ◽  
Venkata. S. Bhadram ◽  
Chandrabhas Narayana ◽  
Aninda J. Bhattacharyya
Keyword(s):  
Ionic Liquids ◽  
Phase Transitions ◽  
Light Scattering ◽  
Solid Phase ◽  
Microscopic Structure ◽  
Temperature Dependent ◽  
Brillouin Light Scattering ◽  
Acoustic Modes ◽  
Structure And Dynamics ◽  
Acoustic Velocities

<p>Pyrrolidinium based ionic liquids are known to be good ionic conductors even in solid-state around room temperature, which is attributed to the highly disordered plastic crystalline phase. Moreover, these ionic liquids are characterized by multiple phase transitions which include plastic, structural glass, and glassy crystal phases with varying levels of molecular disorder. Temperature-dependent Brillouin light scattering is used to investigate the phase transitions in a series of alkylmethylpyrrolidinium Bis(trifluoromethanesulfonyl) imides (P<i><sub>1n</sub></i>TFSI, n=1,2,4). Brillouin spectral features such as the number of acoustic modes, their shape, and linewidth provide the picture of different disordered phases resultant of dynamics at the microscopic scale. The longitudinal and transverse acoustic velocities in different phases are determined from the corresponding acoustic mode frequencies (Brillouin shift). Extremely low acoustic velocities in the solid phase of P<i><sub>11</sub></i>TFSI and P<i><sub>12</sub></i>TFSI are a consequence of a high degree of disorder and plasticity present in the system. Anomalous temperature-dependent behavior of linewidth and asymmetric (Fano) line shape of acoustic modes observed in certain phases of P<i><sub>1n</sub></i>TFSI could be due to the strong coupling between the Brillouin central peak and the acoustic phonons. The present results establish that the Brillouin light scattering technique can be efficiently used to understand the complex phase behavior, microscopic structure, and dynamics of ionic liquids.</p>

Electron Paramagnetic Resonance Study of Cu 2+ in CdCa (CH3COO) 4 • 6H2O Single Crystal

2000 ◽  
Vol 55 (8) ◽  
pp. 729-732
Author(s):  
Hüsey in Kalkan ◽  
Ismet Senel
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystal ◽  
Room Temperature ◽  
Electron Paramagnetic Resonance Study ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Jahn Teller ◽  
Experimental Errors ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Abstract The Electron Paramagnetic Resonance spectra of Cu 2+ in CdCa (CH3COO)4 • 6H2O (cadmium calcium tetraacetate hexahydrate) powder and single crystal have been recorded at 300 and 133 K. The angular variation of the spectra indicated the substitution of the host Cd 2+ with Cu 2+ . The observed values of the g and A hyperfine tensors were found to be temperature dependent, and this dependence is discussed and explained on the basis of dynamic Jahn-Teller effects. The spin-Hamiltonian parameters were found to be axial symmetric at room temperature, whereas they showed deviations from axial symmetry at low temperature. The g and A tensors where found to be coaxial within the limits of experimental errors, and the ground state wave functions of the complex at 300 and 133 K have been constructed.

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