相关论文: Elastic Properties of KH2PO4 at the ferroelectric …
This study employs resonant ultrasound spectroscopy (RUS) to investigate the elastic properties of single crystalline KH$_{2}$PO$_{4}$ (KDP) through the paraelectric to ferroelectric phase transition. Noteworthy anomalies are observed in…
Measurements of the sound velocities in a single crystal of FeSi were performed in the temperature range 4-300 K. Elastic constants $C_{12}$ and $C_{44}$ deviate from a quasiharmonic behavior at high temperature; whereas, $C_{12}$ increases…
The elastic properties of hcp $^4$He samples have been investigated using low frequency (20 Hz to 20 kHz) high sensitivity sound transducers. In agreement with the findings of other workers, most samples studied grew very significantly…
Measurements of the sound velocities in a single crystal of MnSi were performed in the temperature range 4-150 K. Elastic constants, controlling propagation of longitudinal waves reveal significant softening at a temperature of about 29.6 K…
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…
The time dependent cluster approximation called the path probability method (PPM) is applied to a pseudo-spin Ising Hamiltonian of the Slater-Takagi model for KH2PO4-type hydrogen-bonded ferroelectrics in order to calculate the homogeneous…
Dielectric spectroscopy of $SrTiO_3$ single crystal over a broad range of microwave frequency using quasi $TE_{m,1,1}$ and quasi $TM_{m,1,1}$ modes reveals crystal asymmetry from typical measurement of $Q$-factor, transmission or frequency…
We report the discovery of a very large thermoelectric power over -400 microV K-1 in the whisker crystals of a one-dimensional telluride Ta4SiTe4, while maintaining a low electrical resistivity of rho = 2 mohm cm, yielding a very large…
The structural features and physical properties of the antiferromagnetic K0.8Fe1.6Se2 (so called K2Fe4Se5 phase) have been studied in the temperature range from 300K up to 600K. Resistivity measurements on both single crystal and…
We present the results of the thermodynamic theory of piezoelectric ferroelectrics and of the phenomenological theory of thermodynamic characteristics of the KH$_{2}$PO$_{4}$ type ferroelectrics. Available experimental data for the…
We investigate bulk superconductivity in a high-quality single crystal of Bi$_2$Pd ($\beta$-Bi$_2$Pd, space group; I4/mmm) at temperatures less than 5.4 K by exploring its electrical resistivity, magnetic susceptibility, and specific heat.…
We examine the resistivity and thermopower of single crystal specimens of the pyrochlore oxide Cd2Re2O7 at pressures up to 2GPa. Thermopower proves to be a sensitive tool in the study of the phase diagram of Cd2Re2O7. The 200K…
The results for dilatometric, ultrasonic velocity and the domain struct-ure studies of Cs3Bi2I9 crystals in the course of ferroelastic phase trans-ition are presented. It is shown that the phase transition in Cs3Bi2I9 is of the first order.…
For CuInP$_2$S$_6$ layered ferrielectric crystal, that is most investigated among wide family of van der Waals ferroics MM$'$P$_2$X$_6$ (M - Cu, Ag; M$'$ - In, Bi, Cr, $\dots$; X - S, Se), by Brillouin spectroscopy the temperature…
High-quality single crystals of K0.8Fe2Se1.4S0.4 are successfully synthesized by self-flux method with the superconducting transition temperatures Tconset = 32.8 K and Tczero = 31.2 K. In contrast to external pressure effect on…
Low temperature studies of the behavior of the sound velocity and attenuation of acoustic modes have been performed on a single crystal NdFe_3(BO_3)_4. Transitions of the magnetic subsystem to the antiferromagnetically ordered state at T_N…
Temperature dependent electrical resistivity, crystal structure and heat capacity measurements reveal a resistivity drop and metal to semiconductor transition corresponding to first order structural phase transition near 400 K in Ca3Co4O9.…
Full pattern Le-Bail refinement using x-ray powder diffraction profiles of Sr1-xCaxTiO3 for x=0.02, 0.04 in the temperature range 12 to 300 K reveals anomalies in the unit cell parameters at 170, 225 K due to an antiferrodistortive (cubic…
High-quality single crystals of KCo$_2$As$_2$ with the body-centered tetragonal ThCr$_2$Si$_2$ structure were grown using KAs self flux. Structural, magnetic, thermal, and electrical transport were investigated. No clear evidence for any…
A transition in a spheroidal particle from the paraelectric to the ferroelectric phase as well as dynamic susceptibility are studied without approximation in the paraphase. It is assumed that the surface charge is compensated and the…