Evidence for a new phase transition in Rb2ZnCl4 by Raman scattering

Francke, E.; Postollec, M. Le; Mathieu, Jean‐Paul; Poulet, H.

doi:10.1016/0038-1098(80)90720-6

Cited by 53 publications

(6 citation statements)

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“…For temperatures slightly above the lock-in transition a soliton regime has been described ( [10] and references therein). A further phase transition to a monoclinic phase is observed at T 3 = 72 K [11,12].…”

Section: Introductionmentioning

confidence: 90%

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Pressure-induced disorder in Rb₂ZnCl₄

Machon¹,

Grzechnik²,

Friese³

2009

J. Phys.: Condens. Matter

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Rb(2)ZnCl(4) in the normal phase (T = 308-313 K) has been studied under pressure by means of single-crystal x-ray diffraction up to 3.84 GPa and Raman spectroscopy up to 5.9 GPa. No pressure-induced phase transition has been observed but an orientational disorder of the tetrahedra is enhanced with the pressure. At the same time a partial one-dimensional correlation of some chlorine atoms might be favoured at high pressures. Raman spectra in the incommensurate phase (T = 293 K) were collected to higher pressure (24.2 GPa) varying the pressure-transmitting medium. The hydrostaticity during the compression is shown to affect drastically the broadness of the Raman peaks, leading to an amorphous-like spectrum in the least hydrostatic case.

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Section: Introductionmentioning

confidence: 90%

“…The tetrahedral angles range from 104.4(6)-119.8(6) • (combination I and II) and 103.7(13)-118.4(7) • (the combinations III and IV). At 0.69 GPa the angular distortion would be considerably higher for the combinations III and IV (101.4(10)-121.5 (11) • ).…”

Section: X-ray Diffraction At T = 308 Kmentioning

confidence: 96%

Pressure-induced disorder in Rb₂ZnCl₄

Machon¹,

Grzechnik²,

Friese³

2009

J. Phys.: Condens. Matter

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“…The INC phase is very broad (T = 302 K, T, = 189 K), 6 varying from 0.083 at to 0.047 at T, (Gesi and Iizumi, 1979). Below 72 K probably a further cell multiplying phase transition occurs, as evidenced by the observation of new lines and a totally symmetric soft mode below this temperature in Raman scattering by Francke, LePostollec, Mathieu and Poulet (1980a). The frequency of this soft mode fulfills the classical law w, = 2.2(72 -7')'12 cm-' and the mode remains underdamped till -64 K.…”

Section: 23mentioning

confidence: 96%

Dielectric and light scattering spectroscopy of incommensurate phases in crystals

Petzelt

1981

Phase Transitions

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Dielectric and light scattering spectroscopy are the most sensitive methods for the direct observation of low-frequency excitations in incommensurate phases. In several cases they have been successfully used for the observation of amplitudon and phason modqs. Whereas the amplitudon below the normal-incommensurate transition temperature behaves in a similar way to soft modes at common structural transitions, the phason represents a qualitatively new feature of incommensurate phases. All the corresponding experimental data published up to the middle of 1980 are reviewed and consistently interpreted taking into account the specific selection rules recenily derived. The necessary theoretical background is discussed qualitatively. C 0 NTE NTS

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“…Rb 2 ZnCl 4 undergoes successive phase transitions from a paraelectric phase ͑N phase͒ to an incommensurate phase ͑IC phase͒ at T C3 = 303 K, to a ferroelectric commensurate phase ͑C phase͒ at T C2 = 192 K, and to a lowest-temperature phase at T C1 =75 K. [4][5][6][7][8] The paraelectric unit cell contains eight Rb ions, which belong to two crystallographically inequivalent sites, Rb͑1͒ and Rb͑2͒. 1-3 This family of crystals has attracted the attention of investigators for many decades because of the great diversity of their successive structural phase transitions.…”

Section: Introductionmentioning

confidence: 99%

R 87 b and C133s nuclear magnetic resonance study of the structural properties of mixed RbxCs2−xZnCl4 (x=, 1, and 2) crystals

Lim

2010

Journal of Applied Physics

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Articles you may be interested inStudy on the paramagnetic relaxation mechanisms by R 87 b nuclear magnetic resonance in Rb 2 MnCl 4 crystals of A 2 B X 4 type Study of the structural phase transitions in RbCuCl 3 and CsCuCl 3 single crystals with the electric-magnetictype interactions using a R 87 b and C 133 s nuclear magnetic resonance spectrometer Structure and photostimulated luminescent properties of Eu-doped M 2 Ba X 4 ( M = Cs , Rb; X = Br , Cl)The structures of mixed Rb x Cs 2−x ZnCl 4 ͑x = 0, 1, and 2͒ single crystals grown by using the slow evaporation method were determined with x-ray diffraction. In addition, the NMR spectra and the spin-lattice relaxation times, T 1 , of the 87 Rb and 133 Cs nuclei of the three crystals were determined by using nuclear magnetic resonance ͑NMR͒ spectroscopy. The spin-lattice relaxation times, T 1 , of the Cs-based compounds are very much longer than those of the Rb-based compounds. The differences between the T 1 values of the Rb and Cs nuclei are due to the difference between their electric quadrupole moments. Further, we analyzed the crystallographic structures of these crystals by considering the occupation probabilities ͑Rb or Cs͒ of the two cationic sites. Our NMR experimental results confirm that there are two crystallographically inequivalent Rb sites, Rb͑1͒ and Rb͑2͒, in Rb 2 ZnCl 4 and two crystallographically inequivalent Cs sites, Cs͑1͒ and Cs͑2͒, in Cs 2 ZnCl 4 . And, only one Rb site and only one Cs site in RbCsZnCl 4 was obtained. The Cs and Rb occupation rates of each of the two available sites, A 1 and A 2 , were determined from the NMR signals.

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Evidence for a new phase transition in Rb2ZnCl4 by Raman scattering

Cited by 53 publications

References 5 publications

Pressure-induced disorder in Rb₂ZnCl₄

Pressure-induced disorder in Rb₂ZnCl₄

Dielectric and light scattering spectroscopy of incommensurate phases in crystals

R 87 b and C133s nuclear magnetic resonance study of the structural properties of mixed RbxCs2−xZnCl4 (x=, 1, and 2) crystals

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Evidence for a new phase transition in Rb2ZnCl4 by Raman scattering

Cited by 53 publications

References 5 publications

Pressure-induced disorder in Rb2ZnCl4

Pressure-induced disorder in Rb2ZnCl4

Dielectric and light scattering spectroscopy of incommensurate phases in crystals

R 87 b and C133s nuclear magnetic resonance study of the structural properties of mixed RbxCs2−xZnCl4 (x=, 1, and 2) crystals

Contact Info

Product

Resources

About

Pressure-induced disorder in Rb₂ZnCl₄

Pressure-induced disorder in Rb₂ZnCl₄