Related papers: Soft Modes and Relaxor Ferroelectrics
We study the free energy landscape of a minimal model for relaxor ferroelectrics. Using a variational method which includes leading correlations beyond the mean-field approximation as well as disorder averaging at the level of a simple…
New relaxor ferroelectric system has been synthesized. BLTN exhibits a smeared maximum of permittivity, characteristic of classic relaxor behaviour, with a peak shift from 185 K at 100 Hz to 300 K at 1 GHz. BNTN undergoes a first order…
Dielectric properties of BTZ-BCT ceramics were probed in the frequency range from 10 Hz to 100 THz in a broad temperature range (10-900 K). Polar soft phonon observed in infrared spectra softens with cooling, however below 500 K its…
Inelastic and elastic neutron scattering have been used to study a single crystal of the Ni$_{54}$Mn$_{23}$Al$_{23}$ Heusler alloy over a broad temperature range. The paper reports the first experimental determination of the low-lying…
We report an extensive study on the zero field ground state of a powder sample of the pyrochlore $\mathrm{Yb_2Ti_2O_7}$. A sharp heat capacity anomaly that labels a low temperature phase transition in this material is observed at 280 mK.…
Raman scattering experiments on LaFeAsO with splitted antiferromagnetic (T_AFM = 140 K) and tetragonal-orthorhombic (T_S = 155 K) transitions show a quasi-elastic peak (QEP) in B2g symmetry (2 Fe tetragonal cell) that fades away below…
In the field of thermoelectric materials and devices, improving energy conversion efficiency remains a long-standing challenge. As a promising approach to address this issue, utilizing energy-dependent electron-scattering beyond the…
Experimental data obtained for PbFe$_{1 / 2}$Ta$_{1 / 2}$O$_{3}$ (PFT) and NaNbO$_{3}$: Gd (NaNbGd) single crystals show a diffused dielectric permittivity peak that is inherent to relaxor ferroelectrics. However some deviations from the…
We present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 along [010] and TA2 along [110]) and two low energy optic…
Combining our comprehensive investigations of polarization evolution, soft-mode by Raman scattering and microstructure by TEM, and the results reported in the literatures, we show that prototypical relaxor Pb(Mg1/3Nb2/3)O3 (PMN) is…
We perform Glauber model calculations of the antiproton-nucleus elastic and quasielastic scattering and absorption in the beam momentum range $\sim 0.5\div10$ GeV/c. A good agreement of our calculations with available LEAR data and with…
We investigate the low temperature behaviour of Pb(In$_{1/2}$Nb$_{1/2}$)O$_{3}$-Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$-PbTiO$_{3}$ using dielectric permittivity measurements. We compare single crystal plates measured in the [001] and [111]…
The effect of the electron temperature on both the light absorption and the scattering by metal nanoparticles (MNs) with excitation of the surface plasmon electron vibrations is studied in the framework of the kinetic theory. The formulae…
We develop a theory to study the characteristics of dipolar / strain fluctuations in perovskite relaxors. In addition to the soft TO and TA phonons, we take into account another freedom of motion associated with the random hopping of…
Neutron inelastic scattering measurements of the polar TO phonon mode in the cubic relaxor Pb(Mg1/3Nb2/3)O3, at room temperature, reveal anomalous behavior similar to that recently observed in the Pb(Zn1/3Nb2/3)_{0.92}Ti_{0.08}O3 system in…
Broadband dielectric spectroscopy from Hz up to the infrared (IR) range and temperature interval 10-300 K was carried out for xBaZrO3-(1-x)BaTiO3 (BZT-x, x = 0.6, 0.7, 0.8) solid solution ceramics and compared with similar studies for x =…
A neutron scattering investigation of the magnetoelectric coupling in PbFe_{1/2}Nb_{1/2}O_{3} (PFN) has been undertaken. Ferroelectric order occurs below 400 K, as evidenced by the softening with temperature and subsequent recovery of the…
We measured the temperature dependence of low-frequency Raman spectra in Li$_2$RuO$_3$, and observed multipeak quasielastic scattering in the Ru honeycomb polarizations below and above the magnetostructural transition temperature. We…
We report high $q$-resolution neutron scattering data on PMN-$x$PT single crystals with $x=20%$ and 27%. No rhombohedral distortion occurs in the 20PT sample for temperatures as low as 50 K. On the other hand, the 27PT sample transforms…
We use variable-temperature x-ray thermal diffuse scattering and inelastic scattering to investigate the lattice dynamics in single crystals of multiferroic CaMn7O12 which undergo a series of orbital and magnetic transitions at low…