Showing papers by "Pushan Ayyub published in 1986"
TL;DR: The nature of the variations of lattice and internal frequencies with changes in A 3+ -ion concentration is qualitatively discussed with particular reference to the ferroelectric soft mode.
Abstract: Raman scattering and infrared absorption studies of ferroelectric SbNbO 4 , antiferroelectric BiNbO 4 , and the solid solution (Sb 1-x Bi x )NbO 4 for 0 −1 are reported. These are the first vibrational spectroscopic investigations in these stibiotantalite-type systems. Symmetry assignments are proposed for the internal modes. Such an assignment is shown to lead to a consistent set of values for the local force constants calculated under the general quadratic valence force field. The nature of the variations of lattice and internal frequencies with changes in A 3+ -ion concentration is qualitatively discussed with particular reference to the ferroelectric soft mode.
48 citations
TL;DR: In this paper, the magnetic hyperfine field in 120 A YFeO 3 microcrystals just below the superparamagnetic blocking temperature, as well as at 5 K are found to be surprisingly low, and the observed features cannot be understood in terms of either collective magnetic citations or superferromagnetism.
11 citations