相关论文: Anomalous structural behavior and antiferroelectri…
X-ray diffraction studies on a Pb(Zn$_{1/3}$Nb$_{2/3}$)O$_3$ (PZN) single crystal sample show the presence of two different structures. An outer-layer exists in the outer most $\sim$ 10 to 50~$\mu$m of the crystal, and undergoes a…
Structural changes in REMnO3 (RE= Y, Ho, Lu) under high pressure were examined by synchrotron x-ray diffraction methods at room temperature. Compression occurs more readily in the ab plane than along the c-axis. Under hydrostatic pressure…
We report a Raman scattering investigation of multiferroic bismuth ferrite BiFeO3 epitaxial (c-axis oriented) thin films from -192 to 1000C. Phonon anomalies have been observed in three temperature regions: in the gamma-phase from 930C to…
The novel ferroelectric-like structural transition observed in metallic LiOsO$_3$ [Y. Shi et al., Nat. Mater. 12, 1024 (2013)], has invoked many theoretical and experimental interests. In this work, we have performed polarized and…
Synchrotron X-ray diffraction (XRD) experiments were performed on the network compounds Ba1-xSrxAl2O4 at temperatures between 15 and 800 K. The ferroelectric phase of the parent BaAl2O4 is largely suppressed by the Sr-substitution and…
We report Electron Paramagnetic Resonance measurements on single crystalline and powder samples of Nd_0.5Ca_0.5MnO_3 across the charge-ordering transition at T_co=240 K down to the antiferromagnetic ordering transition at T_N = 140 K. The…
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…
The changes of polarizational, elastic and structural properties of mutiferroic BiFeO3 under [111] direction uniaxial stress are calculated using density functional theory within the Perdew-Burke- Ernzerhof revised for solids (PBEsol) + U…
The normal ferroelectric to paraelectric phase transition in model ferroelectric materials such as BaTiO3 is typically characterized by a sharp, well-defined dielectric constant peak at a specific transition temperature. However, under…
X-ray diffraction, dynamical mechanical analysis and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal I4/mcm due to…
Environmentally benign (1-x)Ba(Ti$_{0.8}$Zr$_{0.2}$)O$_3$-x(Ba$_{0.7}$Ca$_{0.3}$)TiO$_3$ (BZT-BCT) ceramics are promising materials due to their remarkable high piezoresponse [Liu and Ren, Phys. Rev. Lett. \textbf{103}, 257602 (2009)]. In…
The structural, magnetic and resistive properties of (La1-yYy)FeAsO compounds (y = 0.10, 0.20, 0.30) have been investigated by means of X-ray and neutron powder diffraction as well as by resistivity measurements. The temperatures at which…
High temperature powder neutron diffraction experiments have been conducted around the reported beta-gamma, insulator-metal phase transition (~ 930 C) in BiFeO3. The results demonstrate that while a small volume contraction is observed at…
To unravel the origin of the dielectric anomaly at the antiferromagnetic ordering of magnetoelectric Bi$_2$Fe$_4$O$_9$ we performed neutron powder diffraction measurements across the N$\acute{\rm e}$el temperature, $T_{\rm N}$. Both local…
Measurements of temperature-dependent resistance and magnetization under hydrostatic pressures up to 2.13 GPa are reported for single-crystalline, superconducting BaBi$_3$. A temperature - pressure phase diagram is determined and the…
We investigated the temperature evolution of crystal structure of orthorhombic CoZr3, which is a superconductor with a transition temperature of 4.3 K, by synchrotron and laboratory (CuK{\alpha}) X-ray diffraction. Uniaxial negative thermal…
The phase purity and crystal structure of PLTA samples (synthesized via sol-gel process) were confirmed using synchrotron x-ray powder diffraction (wavelength, lmbda= 0.44573 A. Rietveld analyses of powder x-ray diffraction data confirmed…
Thermal excitations typically reduce the electric polarization in ferroelectric materials. Here, we show by means of first-principles calculations that multiferroic BiFe$_{1-x}$Co$_{x}$O$_{3}$ solid solutions with $0.25 \le x \le 0.50$…
Magnetic and crystallographic transitions in the Cairo pentagonal magnet Bi2Fe4O9 are investigated by means of infrared synchrotron-based spectroscopy as a function of temperature (20 - 300 K) and pressure (0 - 15.5 GPa). One of the phonon…
We have determined the crystal structures and superconducting transition temperatures of La1.48Nd0.4Sr0.12CuO4 under nearly hydrostatic pressures in diamond anvil cells to 5.0 GPa and 19.0 GPa, respectively. Synchrotron x-ray powder…