Underdamped soft tunnelling modes in hydrogen‐bonded ferroelectrics below T

Blinc, R.; Lavkenčič, B.; Levstek, I.; Smolej, V.; Žekš, B.

doi:10.1002/pssb.2220600128

Cited by 117 publications

(165 citation statements)

References 13 publications

Supporting

Mentioning

154

Contrasting

Order By: Relevance

“…FE materials normally contain electric dipoles. In the framework of spin dynamics, the electric dipoles are represented by the pseudospins, with a transverse Ising model to characterize the local energy [20]. The transverse Ising model was conjectured by P. G. de Gennes [21] and R. J. Elliott [22], for the description of order-disorder KDP-type ferroelectrics (e.g.…”

Section: Spin and Pseudospin Modelsmentioning

confidence: 99%

Dynamic response in a finite size composite multiferroic thin film

Wang

Grimson

2016

Journal of Applied Physics

View full text Add to dashboard Cite

Composite multiferroics, heterostructures of ferromagnetic (FM) and ferroelectric (FE) materials, are characterized by a remarkable magnetoelectric effect at the interface. Previous work has supported the ferromagnetic structure with magnetic spins and the ferroelectric with pseudospins which act as electric dipoles in a microscopic model, coupled with a magnetoelectric interaction [J. Appl. Phys. 118, 124109 (2015)]. In this work, by solving the stochastic Landau-Lifshitz-Gilbert equation, the electric-field-induced magnetization switching in a twisted boundary condition has been studied, and a behavior of domain wall in the ferromagnetic structure is discussed.

show abstract

Section: Spin and Pseudospin Modelsmentioning

confidence: 99%

Dynamic response in a finite size composite multiferroic thin film

Wang

Grimson

2016

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…By performing the corresponding calculations one finds: .18)). Consequently, for the parameters of the pseudospin Hamiltonian (4.6) the following expressions are obtained: 33) where the reduced average quadratic "slow" displacement (4.19) becomes r ≡ B A r…”

Section: Approximation Of a Double Well By Two Truncated Harmonic Oscmentioning

confidence: 99%

“…the frequency of the pseudospin (tunnelling) mode is expressed in the well-known but slightly modified form [7,11,[33][34][35];…”

mentioning

confidence: 99%

The Unified Model Description of Order-Disorder and Displacive Structural Phase Transitions

Stamenković¹

1998

Condens. Matter Phys.

View full text Add to dashboard Cite

A series of co-authors' studies [1][2][3][4][5][6][7] devoted to the unified model description of structural phase transitions (SPT) in ferroelectrics and related materials are reviewed and partly innovated.Starting from a general Hamiltonian of pair-coupled anharmonic (quartic) oscillators, together with the concept of local normal coordinates, a unified model description of both order-disorder and displacive types of SPT-systems is proposed. Within the framework of the standard variational procedure, a hybridized pseudospin-phonon Hamiltonian is formulated by introducing variables corresponding to phonon, magnon-like(flipping) and nonlinear(domain-wall-like) displacements of atoms participating in SPT. This is achieved by representing the cooperative atomic motion onto several quasiequilibrium positions (in the simplest case, two) as slow tunnelling displacement (decomposed into magnon-like and soliton-like deviations), in addition to comparatively fast phonon oscillations around inhomogeneous momentary rest positions, in turn induced by domain-wall-like (soliton) excitations.The qualitative and quantitative analyses show that SPT (of the first or second order) can be either of a displacive (governed by a phonon soft mode), order-disorder (governed by a tunnelling-magnon-like soft mode) or of a mixed type, depending on both the coupling energy between atoms and their zero-point vibrational energy. In the critical temperature region, the domain-wall-like excitations bring on the formation of microdomains (precursor clusters of the ordered phase) which induce SPT of the Ising type universality class. The incomplete softening of the phonon or pseudomagnon mode occurs and a central peak due to slow cluster relaxation appears in the spectral density of excitations.

show abstract

“…However, as the soft mode is important, the soft mode scattering cross-section is reduced near Τ^ in both polymer and monomer [10,18] to a signature equivalent to a relaxation process. In such a case, a dispersion should be observed [19].…”

Section: Introductionmentioning

confidence: 99%

Dielectric Study of Pure Polymer and Mixed Monomer-Polymer Single Crystals of pTS Diacetylene: a Comparison with Neutron Scattering Results

et al. 1995

View full text Add to dashboard Cite

Temperature and frequency dependences of the electric permittivity in mixed monomer-polymer single crystals of the diacetylene pTS (2,4-hexadiynylene bis(p-toluenesulphonate)) are reported. The dependences were determined in the temperature range 100-250 K, and in the frequency range 100 Hz-1 MHz. Two types of single crystals were studied: nearly-fully polymerized ones, and those containing ca. 20% of polymer in the monker matrix. The dynamics is characterized by a high-frequency response (v > 3 GHz) which corresponds to the soft mode analysed previously by the Raman and neutroii inelástic scatterings. At low frequencies (v < 1 kHz), another component is observed, its dielectric intensity peaking around the transition temperature in the fully polymerized crystals. The results are consistent with the results obtained from NMR and neutron scattering experiments.

show abstract

Underdamped soft tunnelling modes in hydrogen‐bonded ferroelectrics below T

Abstract: Underdamped soft tunnelling modes, which disappear on deuteration, are observed in KHZP04 type crystals below Tc in addition to a central mode which exists both above and below Tc. These results can be understood in terms of a Bloch type description of pseudo‐spin motion.

Cited by 117 publications

References 13 publications

Dynamic response in a finite size composite multiferroic thin film

Dynamic response in a finite size composite multiferroic thin film

The Unified Model Description of Order-Disorder and Displacive Structural Phase Transitions

Dielectric Study of Pure Polymer and Mixed Monomer-Polymer Single Crystals of pTS Diacetylene: a Comparison with Neutron Scattering Results

Contact Info

Product

Resources

About