Related papers: Volume Collapse Without a Structural Transition in…
Low Mach number collisionless shocks are routinely observed in the solar wind and upstream of planetary bodies. However, most in situ observations have lacked the necessary temporal resolution to directly study the kinetic behavior of ions…
We study the spherical collapse of non-top-hat matter fluctuations in the presence of dark energy with arbitrary sound speed. The model is described by a system of partial differential equations solved using a pseudo-spectral method with…
The self-interaction corrected local spin density (SIC-LSD) formalism and the standard GGA treatment of the exchange-correlation energy have been applied to study the collapse of the magnetic moment of Fe impurities in MgO. The system…
The phase stability of the MgMn2O4 spinel has been studied by means of high-pressure X-ray diffraction for pressures up to 30 GPa. Two samples with different inversion degrees have been considered. Both spinels undergo a phase transition…
In this letter, we report that the superconductivity transition temperature in beta-Fe1.01Se increases from 8.5 to 36.7 K under applied pressure of 8.9 GPa. It then decreases at higher pressure. A dramatic change in volume is observed at…
The temperature dependence of the structural and magnetic properties of wolframite-type FeWO4 were studied in situ by high pressure neutron diffraction. Neutron diffraction measurements were performed at the XtremeD instrument at the…
Large-amplitude electrostatic fluctuations are routinely observed by spacecraft upon traversal of collisionless shocks in the heliosphere. Kinetic simulations of shocks have struggled to reproduce the amplitude of such fluctuations,…
We have observed a softening of phonons and a structural phase transition in a superconducting Ba0.59K0.41BiO3 (Tc = 31 K) single crystal using elastic and inelastic neutron scattering measurements. The soft phonon occurs for the [111]…
We report muon spin relaxation/rotation (uSR) measurements of single crystal Ba(Fe1-xCox)2As2 with x=0.038 and 0.047. Zero field (ZF)-uSR and Transverse field (TF)-iSR measurements of these underdoped samples find the presence of magnetism…
High quality thin films of the ferromagnetic semiconductor EuO have been prepared and were studied using a new form of spin-resolved spectroscopy. We observed large changes in the electronic structure across the Curie and metal-insulator…
We present results from a detailed experimental investigation of LaFeAsO, the parent material in the series of "FeAs" based oxypnictide superconductors. Upon cooling this material undergoes a tetragonal-orthorhombic crystallographic phase…
The crystal structure of the layered, perovskite-related LaTiO_3.41 (La_5Ti_5O_{17+\delta}) has been studied by synchrotron powder x-ray diffraction under hydrostatic pressure up to 27 GPa (T = 295 K). The ambient-pressure phase was found…
We report on the structural phase transitions in the S doped FeSe superconductor by powder synchrotron X ray diffraction at high pressures up to 18.5 GPa under compression and decompression modes. In order to create high quasi hydrostatic…
We report the in-plane optical measurements on Na$_x$CoO$_2$ with 0.18$\leq$x$\leq$0.92. The crystal growth and characterization were described in detail. The spectral weight increases monotonically with decreasing x. For sample with the…
We have prepared the newly discovered Fe-based superconducting material $\rm LaO_{1-x}F_xFeAs$ ($0\leq x\leq 0.2$) in polycrystalline form and have investigated the samples by means of structural, thermodynamic and transport measurements.…
A new iron-oxychalcogenide (CaO)(FeSe) was obtained which crystallizes in the orthorhombic space group Pnma (No. 62) with a = 5.9180(12) {\AA}, b = 3.8802(8) {\AA}, c = 13.193(3) {\AA}. The unique structure of (CaO)(FeSe) is built up of a…
Raman spectroscopy examination of the 25 deg-C water freezing under compression revealed transition from 1.35 GPa to 0.86 GPa upon ice being formed at continued volume change. The transition is associated with a slight blue shift of the…
MnAu$_{2}$ is a spin-spiral material with in-plane ferromagnetic Mn layers that form a screw-type pattern around a tetragonal $c$ axis. The spiral angle $\theta$ was shown using neutron diffraction experiments to decrease with pressure, and…
Using sedimentation to obtain precisely controlled packings of noncohesive spheres, we find that the volume fraction $\phi_{\rm RLP}$ of the loosest mechanically stable packing is in an operational sense well defined by a limit process.…
Recent experiments on Pd$_{3}$Fe intermetallics [Phys. Rev. Lett. 102, 237202 (2009)] have revealed that the system behaves like a classical invar alloy under high pressure. The experimental pressure-volume relation suggests an anomalous…