Related papers: Lattice dynamics across the ferroelastic phase tra…
Up to now the crystallographic structure of the magnetoelectric perovskite EuTiO3 was considered to remain cubic down to low temperature. Here we present high resolution synchrotron X-ray powder diffraction data showing the existence of a…
3$d$ based double perovskite materials have received much attention in recent years due to their exotic magnetic structure and magneto-electric coupling. In this work we have prepared and studied the nano-crystalline sample of…
Time-domain femtosecond laser spectroscopic measurements of the ultrafast lattice dynamics in 2H-MoTe2 bulk crystals were carried out to understand the carrier-phonon interactions that govern electronic transport properties. An unusually…
Infrared reflectance spectra of an epitaxial Bi2FeCrO6 thin film prepared by pulsed laser deposition on LaAlO3 substrate were recorded between 10 and 900 K. No evidence for a phase transition to the paraelectric phase was observed, but some…
Transition-metal dichalcogenide IrTe2 has attracted attention because of striped lattice, charge ordering and superconductivity. We have investigated the surface structure of IrTe2, using low energy electron diffraction (LEED) and scanning…
We have studied the cubic to tetragonal phase transition in epitaxial SrTiO$_3$ films under various biaxial strain conditions using synchrotron X-ray diffraction. Measuring the superlattice peak associated with TiO$_6$ octahedra rotation in…
PbTe crystals have a soft transverse optical phonon mode in the terahertz frequency range, which is known to efficiently decay into heat-carrying acoustic phonons, resulting in anomalously low thermal conductivity. Here, we studied this…
Sodium niobate (NaNbO3) exhibits most complex sequence of structural phase transitions in perovskite family and therefore provides as excellent model system for understanding the mechanism of structural phase transitions. We report…
We have investigated the phonon and the magnetic excitations in LaCoO3 by inelastic neutron scattering measurements. The acoustic phonon dispersions show some characteristic features of the folded Brillouin zone (BZ) for the rhombohedrally…
Frequency-dependent and temperature-dependent dielectric measurements are performed on double perovskite Tb$_2$NiMnO$_6$. The real ($\epsilon_1$) and imaginary ($\epsilon_2$) parts of dielectric permittivity show three plateaus suggesting…
Using first-principles calculations we examine the crystal structures and phase transitions of nitride perovskite LaWN$_3$. Lattice dynamics calculations indicate that the ground-state structure belongs to space group $R3c$. Two competitive…
The lattice dynamics of the $\rm YMnO_3$ magneto-electric compound has been investigated using density functional calculations, both in the ferroelectric and the paraelectric phases. The coherence between the computed and experimental data…
Parent compounds of Fe-based superconductors undergo a structural phase transition from a tetragonal to an orthorhombic structure. We investigated the temperature dependence of the frequencies of transverse acoustic (TA) phonons that…
Quasi-2D van der Waals ferromagnet Fe$_4$GeTe$_2$, featuring the simultaneous presence of high Curie temperature ($T_\mathrm{C}$ $\sim 270$ K) and a spin-reorientation transition at $T_\mathrm{SR}$ $\sim 110$ K, is a rare system where…
The magnetism of double perovskites is a complex phenomenon, determined from intra- or interatomic magnetic moment interactions, and strongly influenced by geometry. We take advantage of the complementary length and time scales of the muon…
We investigated microscopic lattice states in the donor-acceptor ionic Mott insulator, TTF-BA, by $^{79}$Br-NQR spectroscopy to explore cross-correlated fluctuations between spin, charge and lattice. A ferroelectric transition with lattice…
A comparative analysis of the structural phase transitions of EuTiO3 and SrTiO3 (at TS = 282 and 105 K, respectively) is made on the basis of phonon-dispersion and density functional calculations. The phase transition of EuTiO3 is predicted…
Oxide double perovskites wherein octahedra formed by both 3d elements and sp-based heavy elements give rise to unconventional magnetic ordering and correlated quantum phenomena crucial for futuristic applications. Here, by carrying out…
Remarkable exploitation of valence and lattice mismatch in epitaxial ferroelectric heterostructures generates physical effects not classically expected for perovskite oxides, such as 2D electron gas and polar skyrmions. However the…
In ferroelectricity, atomic-scale dipole moments interact collectively to produce strong electro-mechanical coupling and switchable macroscopic polarization. Hence, the functionality of ferroelectrics emerges at a solid-solid phase…