Raman studies of the 223 K phase transition in (NH4)2SO4single crystal
- 31 December 1990
- journal article
- Published by IOP Publishing in Journal of Physics: Condensed Matter
- Vol. 2 (51) , 10607-10613
- https://doi.org/10.1088/0953-8984/2/51/030
Abstract
The temperature dependence of the z(yy)x Raman spectrum was studied in (NH4)2SO2 single crystal in the temperature range 300-100 K. The temperature dependence of the NH4 translational Raman bands in the region of 200 cm-1 seems to support the hypothesis that the peculiar temperature dependence of the spontaneous polarization in (NH4)2SO4 single crystal may be ascribed to the competing polarization contributions from the NH4+(I) and NH4+(II) dipoles of opposite direction with differing reorientational relaxation temperature dependences, and also the NH4+-SO42 displacive lattice polarization, which was neglected in the point-charge model.Keywords
This publication has 25 references indexed in Scilit:
- Dielectric dispersion of (NH4)2SO4in the near-millimetre and far-infrared range: manifestations of disorderJournal of Physics C: Solid State Physics, 1988
- Phenomenological theory of the phase transition in improper ferroelectric ammonium sulphateJournal of Physics C: Solid State Physics, 1987
- The phase transition in ammonium sulphate: dynamics of deuterated NH4+ions and the heat of transitionJournal of Physics C: Solid State Physics, 1987
- Phase transition and temperature dependence of the molecular distortion of ions in ammonium sulphateJournal of Physics C: Solid State Physics, 1986
- Studies of the Crystal Structure of Ammonium Sulfate in Connection with Its Ferroelectric Phase TransitionJournal of the Physics Society Japan, 1981
- Raman scattering study of ferroelectric phase transition in ammonium sulphateSolid State Communications, 1976
- Two-Sublattice Model of Ferroelectric Phase TransitionsJournal of the Physics Society Japan, 1976
- A Point Charge Model for the Ferroelectric Transition in Ammonium SulphatePhysica Status Solidi (b), 1974
- Elastic anomaly in (NH4)2SO4Physica Status Solidi (a), 1973
- A phenomenological theory of dielectric and mechanical properties of improper ferroelectric crystalsPhysica Status Solidi (b), 1972