Rotation-translation coupling in (NH4I)0.5(KI)0.5

Ohl, Michael; Mayr, F.; Reehuis, M.; Schmidt, W.; Loidl, A.

doi:10.1016/s0921-4526(99)01700-7

Cited by 3 publications

(3 citation statements)

References 8 publications

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“…Due to rotational and translational disorder effects in these crystals phonons of the whole Brillouin zone have been observed in the FIR spectra, even above the OG transition. Based on neutron-scattering studies [18,32] the RT coupling becomes dominant below T = 80 K, which is comparable to the temperature dependences of the TO phonons found in the present FIR data. We conclude that the RT coupling does not only influence the longitudinal [32] and transversal [18] acoustic phonons but also the transverse optical phonons.…”

Section: Discussionsupporting

confidence: 89%

“…Based on neutron-scattering studies [18,32] the RT coupling becomes dominant below T = 80 K, which is comparable to the temperature dependences of the TO phonons found in the present FIR data. We conclude that the RT coupling does not only influence the longitudinal [32] and transversal [18] acoustic phonons but also the transverse optical phonons. The strongest effects were detected in the TO modes, which originate from the NX 4 + ↔ I − (X = H, D) vibrations.…”

Section: Discussionsupporting

confidence: 89%

“…For this system no phase diagram has been published so far. However elastic and quasielastic neutron scattering experiments revealed a quasielastic linewidth similar to that in the protonated iodide indicating the existence of an orientational glass state in these systems, too [20].…”

Section: Introductionmentioning

confidence: 85%

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Lattice vibrations in the mixed crystals (NH₄I)_0.3(KI)_0.7, (ND₄I)_0.3(KI)_0.7and (NH₄Br)_0.3(KBr)_0.7

Ohl

Mayr

Reehuis

et al. 2001

J. Phys.: Condens. Matter

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Transverse optical phonons have been studied in (NH 4 I) 0.3 (KI) 0.7 , (ND 4 I) 0.3 (KI) 0.7 and (NH 4 Br) 0.3 (KBr) 0.7 using Fourier-transform infrared techniques. In all materials three phonon modes have been observed in the far-infrared regime and were followed as a function of temperature in detail. While the first low-frequency mode characterizes a sublattice motion of the alkali ions against the halogenides K + ↔ I − and K + ↔ Br − , the second mode involves vibrations of the ammonium molecules against the halogenide ions NH 4 + ↔ I − , ND 4 + ↔ I − and HH 4 + ↔ Br − . Despite the fact that the average symmetry of these crystals is cubic, the transitional and orientational disorder locally breaks the cubic symmetry, the infra-red selection rules are relaxed and, hence, a third phonon contribution appears. Deviations of the temperature dependence of the eigenfrequencies, as expected for anharmonic modes, are interpreted in terms of a rotation-translation coupling where the phonon modes interact with the orientational degrees of freedom.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 89%

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Lattice vibrations in the mixed crystals (NH₄I)_0.3(KI)_0.7, (ND₄I)_0.3(KI)_0.7and (NH₄Br)_0.3(KBr)_0.7

Ohl

Mayr

Reehuis

et al. 2001

J. Phys.: Condens. Matter

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Anomalous thermoelastic behaviour of orientationally disordered (NH4I)x(KI)1−x mixed crystals

Tiwari

Singh

2010

Journal of Physics and Chemistry of Solids

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Field-cooled magnetization measurements of Nd-123 bulk superconductors

Koblischka

Johansen

Murakami

2000

Supercond. Sci. Technol.

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The field-cooled (FC) magnetization M is measured as a function of the applied external field, H a , for various bulk, Nd-based 123 superconductors which exhibit different magnetization-field characteristics (i.e. with and without secondary peak effect). We find that the FC magnetization data reproduce directly the M(H a ) behaviour measured after zero-field cooling. Based on the critical state model, we derive expressions for the field-cooled magnetization, and show that a large M(0) is essential to achieve large trapped fields in superconducting permanent magnets.

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Rotation-translation coupling in (NH4I)0.5(KI)0.5

Cited by 3 publications

References 8 publications

Lattice vibrations in the mixed crystals (NH₄I)_0.3(KI)_0.7, (ND₄I)_0.3(KI)_0.7and (NH₄Br)_0.3(KBr)_0.7

Lattice vibrations in the mixed crystals (NH₄I)_0.3(KI)_0.7, (ND₄I)_0.3(KI)_0.7and (NH₄Br)_0.3(KBr)_0.7

Anomalous thermoelastic behaviour of orientationally disordered (NH4I)x(KI)1−x mixed crystals

Field-cooled magnetization measurements of Nd-123 bulk superconductors

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Rotation-translation coupling in (NH4I)0.5(KI)0.5

Cited by 3 publications

References 8 publications

Lattice vibrations in the mixed crystals (NH4I)0.3(KI)0.7, (ND4I)0.3(KI)0.7and (NH4Br)0.3(KBr)0.7

Lattice vibrations in the mixed crystals (NH4I)0.3(KI)0.7, (ND4I)0.3(KI)0.7and (NH4Br)0.3(KBr)0.7

Anomalous thermoelastic behaviour of orientationally disordered (NH4I)x(KI)1−x mixed crystals

Field-cooled magnetization measurements of Nd-123 bulk superconductors

Contact Info

Product

Resources

About

Lattice vibrations in the mixed crystals (NH₄I)_0.3(KI)_0.7, (ND₄I)_0.3(KI)_0.7and (NH₄Br)_0.3(KBr)_0.7

Lattice vibrations in the mixed crystals (NH₄I)_0.3(KI)_0.7, (ND₄I)_0.3(KI)_0.7and (NH₄Br)_0.3(KBr)_0.7