Brillouin scattering spectroscopy of ferroelectric and ferroelastic phase transitions

Light scattering spectroscopy has played a crucial role in the study of numerous phase transitions and critical phenomena. In the case of structural phase transitions in crystalline solids, high resolution Raman and Brillouin scattering experiments have provided detailed information on the ‘soft modes’, the highly temperature-dependent lattice vibrations whose frequencies fall towards zero at the transition temperature. The condensation of the soft modes precipitates the spontaneous symmetry breaking which inevitably accompanies these transitions. Ferroelectrics comprise a particular class of crystals exhibiting structural phase transitions which have been investigated extensively by light scattering techniques. In addition to numerous soft mode studies, other subtle aspects of these transitions have been investigated by light scattering, including mode interactions and central peaks. In this presentation, the fundamental aspects of structural phase transitions and their relation to light scattering will be reviewed. A number of light scattering studies of ferroelectric crystals spanning the past decade will be summarized and used to illustrate the current level of understanding of these phenomena.

Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.


2018 ◽  
Vol 20 (8) ◽  
pp. 5636-5643 ◽  
Author(s):  
Christoph Möller ◽  
Hanna Fedderwitz ◽  
Claudine Noguera ◽  
Jacek Goniakowski ◽  
Niklas Nilius

STM and DFT calculations are employed to explore structural phase transitions in thin copper-oxide films grown on Au(111).


1985 ◽  
Vol 54 (9) ◽  
pp. 3376-3384 ◽  
Author(s):  
Akira Yoshihara ◽  
Takashi Suzuki ◽  
Tsutomu Yamakami ◽  
Tadao Fujimura

1994 ◽  
Vol 50 (13) ◽  
pp. 8996-9019 ◽  
Author(s):  
Thomas P. Dougherty ◽  
Gary P. Wiederrecht ◽  
Keith A. Nelson ◽  
Mark H. Garrett ◽  
Hans P. Jenssen ◽  
...  

2022 ◽  
Vol 130 (1) ◽  
pp. 84
Author(s):  
А.С. Крылов ◽  
А.Н. Втюрин ◽  
И.А. Гудим ◽  
И.В. Немцев ◽  
С.Н. Крылова

The Raman spectra of four crystals of TbFe3-хGax (BO3) 4 solid solutions (x from 0 to 0.54) were studied in the temperature range from 8 to 350 K. The temperatures of structural phase transitions were determined. The observed spectral behavior is characteristic to condensation and restoration of soft modes. Soft modes are associated with a structural phase transition from the R32 phase to the P3121 phase. The Compositions-Temperature phase diagram was constructed


1979 ◽  
Vol 32 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Terutaro Nakamura ◽  
Yasunori Tominaga ◽  
Masayuki Udagawa ◽  
Seiji Kojima ◽  
Masaaki Takashige

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