X. H. Chen

Neutron-Diffraction Measurements of Magnetic Order and a Structural Transition in the Parent BaFe 2 As 2 Compound of FeAs-Based High-Temperature Superconductors

NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA Los Alamos National Laboratory, Los Alamos, NM 87545, USA Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China

Electronic-Structure-Driven Magnetic and Structure Transitions in Superconducting NaFeAs Single Crystals Measured by Angle-Resolved Photoemission Spectroscopy

C. He, Y. Zhang, B. P. Xie, X. F. Wang, L. X. Yang, B. Zhou , F. Chen, M. Arita, K. Shimada, H. Namatame, M. Taniguchi, X. H. Chen, J. P. Hu and D. L. Feng Department of Physics, Surface Physics Laboratory (National Key Laboratory), and Advanced Materials Laboratory, Fudan University, Shanghai 200433, People’s Republic of China 2 Department of Physics, University of science and technology of China, Hefei, Anhui 230027, People’s Republic of China Hiroshima Synchrotron Radiation Center and Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan. and 4 Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA (Dated: January 18, 2010)

Bulk Properties of the Medium Produced in Relativistic Heavy-Ion Collisions from the Beam Energy Scan Program

© 2017 American Physical Society. We present measurements of bulk properties of the matter produced in Au+Au collisions at sNN=7.7,11.5,19.6,27, and 39 GeV using identified hadrons (π±, K±, p, and p) from the STAR experiment in the Beam Energy Scan (BES) Program at the Relativistic Heavy Ion Collider (RHIC). Midrapidity (|y| < 0.1) results for multiplicity densities dN/dy, average transverse momenta (pT), and particle ratios are presented. The chemical and kinetic freeze-out dynamics at these energies are discussed and presented as a function of collision centrality and energy. These results constitute the systematic measurements of bulk properties of matter formed in heavy-ion collisions over a broad range of energy (or baryon chemical potential) at RHIC.

High pressure study of BaFe2As2—the role of hydrostaticity and uniaxial stress

We investigate the evolution of the electrical resistivity of BaFe(2)As(2) single crystals with pressure. The samples used were from the same batch, grown using a self-flux method, and showed properties that were highly reproducible. Samples were pressurized using three different pressure media: pentane-isopentane (in a piston-cylinder cell), Daphne oil (in an alumina anvil cell) and steatite (in a Bridgman cell). Each pressure medium has its own intrinsic level of hydrostaticity, which dramatically affects the phase diagram. An increasing uniaxial pressure component in this system quickly reduces the spin density wave order and favours the appearance of superconductivity, which is similar to what is seen in SrFe(2)As(2).

Surface and bulk electronic structures of LaFeAsO studied by angle-resolved photoemission spectroscopy

Chang Liu, 2 Yongbin Lee, A. D. Palczewski, 2 J. -Q. Yan, Takeshi Kondo, 2 B. N. Harmon, 2 R. W. McCallum, 3 T. A. Lograsso, and A. Kaminski 2 Division of Materials Science and Engineering, Ames Laboratory, Ames, Iowa 50011, USA Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, USA (Dated: June 7, 2010)

The comparable effects on transport properties in Bi2Sr2Ca1−xPrxCu2Oy and Bi2Sr2Ca1−xYxCu2Oy single crystals

Abstract The in-plane resistivity ρ ab ( T ) of single crystals Bi 2 Sr 2 Ca 1− x Pr x Cu 2 O y ( x ranging from 0 to 0.5) and Bi 2 Sr 2 Ca 1− x Y x Cu 2 O y ( x ranging from 0 to 0.41) has been measured. The doping has dramatic effects on the two systems. In the Pr doped system, T c is suppressed gradually upon doping while the residual resistivity increases strongly. A superconductor–insulator transition is observed when the Pr content reaches about 0.5. In the Y doped system, it is found that ρ ab ( T ) deviates from T -linear behavior at a characteristic temperature T *, which is an evidence of a pseudogap. T * increases with the increase of Y doping. T c is suppressed more rapidly in this system than in the Pr doped system. We suppose that a general correlation exists between anomalous Pr magnetism and a lack of pseudogap in the Pr doped system.

Sim-deintercalation synthesis and electronic conduction of hexagonal potassium tungsten bronze

Abstract A sim-deintercalation process from K 0.58 WO 3 gel obtained by reducing aqueous potassium tungstate has been explored to prepare single-phase hexagonal potassium tungsten bronze (K x WO 3 ) with various x value lower than 0.33. The products were characterized by X-ray powder diffraction and energy dispersive spectroscopy. The relation among phase formation, dopant content and various sim-deintercalation periods was investigated. Resistivity measurements indicate that hexagonal K 0.33 WO 3 bronze prepared in this way shows metallic behavior.

Raman-scattering study of Ba-doped C 60 with t 1 g states

Raman spectra are reported for Ba-doped fullerides

Normal-State Resistivity and Thermoelectric Power of the Bi2Sr2—xLaxCaCu2Oy System

{\mathrm{Ba}}_{x}{\mathrm{C}}_{60}