Related papers: Phonon Dynamics and Multipolar Isomorphic Transiti…
We study the influence of the rattling phonons on superconductivity in $\beta$-pyrochlore KOs$_{2}$O$_{6}$ compound based on the strong-coupling Eliashberg approach. In particular, analyzing the specific heat data we find that the rattling…
We investigate three dimensional anharmonic phonons in tetrahedral symmetry and superconductivity mediated by these phonons. Three dimensional anharmonic phonon spectra are calculated directly by solving Schr\"odinger equation and the…
We report nuclear magnetic resonance studies on the beta-pyrochlore oxide superconductor KOs2O6. The nuclear relaxation at the K sites is entirely caused by fluctuations of electric field gradient, which we ascribe to highly anharmonic low…
Temperature-dependent FAR-infrared reflectivity spectra of partially ordered magnetodielectric La2CoMnO6 is presented, from room temperature up to 675 K. A clear first-ordered structural phase transition (SPT) from a monoclinic structure…
Another phase transition that is probably of first order is found in the beta-pyrochlore oxide superconductor KOs2O6 with a superconducting transition temperature Tc of 9.6 K. It takes place at Tp=7.5 K in the superconducting state in a…
Rattling-induced superconductivity in the {\beta}-pyrochlore oxide KOs2O6 is investigated under high pressure up to 5 GPa. Resistivity measurements in a high-quality single crystal reveal a gradual decrease in the superconducting transition…
We investigate the Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method. Below a critical temperature Tcr, a coexistence of the polaronic and the bipolaronic solutions is found for the same…
Resistivity and specific heat have been measured on a single crystalline sample of the beta-pyrochlore oxide superconductor, KOs2O6. It is found that a second peak in specific heat, which may evidence an unknown phase transition, appears…
To assess electron correlation and electron-phonon coupling in the recently discovered beta-pyrochlores KOs2O6 and RbOs2O6, we have performed specific heat measurements in magnetic fields up to 14 T. We present data from high quality single…
We have carried out temperature-dependent inelastic neutron scattering measurements of YMnO3 over the temperature range 50 - 1303 K, covering both the antiferromagnetic to paramagnetic transition (70 K), as well as the ferroelectric to…
We report temperature evolution of coherently excited acoustic and optical phonon dynamics in superconducting iron pnictide single crystal Ca(Fe_0.944Co_0.056)_2As_2 across the spin density wave transition at T_SDW ~ 85 K and…
Superconducting and normal-state properties of the beta-pyrochlore oxide KOs2O6 are studied by means of thermodynamic and transport measurements. It is shown that the superconductivity is of conventional s-wave type and lies in the…
We investigate a lattice of interacting anharmonic oscillators by using a mean field theory and exact diagonalization. We construct an effective five-state hopping model with intersite repulsions as a model for beta-pyrochlore AOs_2O_6(A=K,…
A miniature Hall sensor array was used to detect magnetic induction locally in the vortex states of the $\beta$-pyrochlore superconductor KOs$_2$O$_6$. Below the first-order transition at $T_{\rm p}\sim 8$ K, which is associated with a…
A complex magnetic order of the multiferroic compound Co3TeO6 has been revealed by neutron powder diffraction studies on ceramics and crushed single crystals. The compound adopts a monoclinic structure (s.g. C2/c) in the studied temperature…
We employ an optical pump-probe technique to study coherent phonon oscillations in Ca$_2$RuO$_4$. We find that oscillation-amplitude of an $A_g$ symmetric phonon mode is strongly suppressed at 260 K, a putative transition point of orbital…
We report on the temperature dependent Raman spectroscopic studies of orthorombic distorted perovskite YCrO3 in the temperature range of 20-300K. Temperature dependence of DC-magnetization measurement under field cooled and zero field…
We report on the microwave, terahertz (THz), infrared and Raman spectroscopic studies of $BiMn_{7}O_{12}$ ceramics, shedding more light into the nature of two structural phase transitions and their possible relation with ferroelectricity in…
Pressure dependence of superconducting transition temperature $T_{\rm c}$ has been determined through the DC magnetic measurements under pressure up to $P$=10 GPa for $\beta$-pyrochlore oxides AOs$_2$O$_6$ with A=Cs ($T_{\rm c}$=3.3 K), Rb…
Magnetic penetration depth ($\lambda$) in a pyrochlore superconductor KOs$_2$O$_6$ was studied by means of muon spin rotation (\msr). The temperature dependence of transverse spin relaxation rate, which is proportional to $\lambda ^{-2}$,…