Momentum dependence of charge excitations in the electron-doped superconductor Nd1.85 Ce0.15 CuO4: a resonant inelastic x-ray scattering study

We report a resonant inelastic x-ray scattering (RIXS) study of charge excitations in the electron-doped high-T(c) superconductor Nd1.85 Ce0.15 CuO4. The intraband and interband excitations across the Fermi energy are separated for the first time by tuning the experimental conditions properly to measure charge excitations at low energy. A dispersion relation with q-dependent width emerges clearly in the intraband excitation, while the intensity of the interband excitation is concentrated around 2 eV near the zone center. The experimental results are consistent with theoretical calculation of the RIXS spectra based on the Hubbard model.     

Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neurons

Background  

Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation.     

Probing interaction of paramagnetic electron with conduction electrons in high Tc superconductor LaSrCuO by (μ-O) spin relaxation

The paramagnetic (μ^-O) state formed at the oxygen site in high T_c LaSrCuO was used to probe an interaction between the localized moment of the paramagnetic electron and the conduction electrons via zero field μ^- spin relaxation. The enhanced relaxation rates consistently observed in the superconducting state of various Sr concentrations are explained as an effect of spin‐pairing in the high T_c supercurrent. This revised version was published online in August 2006 with corrections to the Cover Date.     

Soft phonon behavior and magnetism at the low temperature structural phase transition of La1.65Nd0.35CuO4

We report a neutron scattering investigation of a La_1.65Nd_0.35CuO₄ single crystal which undergoes a second order structural transition with decreasing temperature from a high temperature orthorhombic phase (space group Bmab) to a distinct low temperature orthorhombic phase (space group Pccn) atT _s =76 K. The transition is induced by the softening of the phonon mode that involves rotations of the tilt axis of the CuO₆ octahedra. Antiferromagnetic long range order is established belowT _N =316 K, and a hysteretic reorientation to a noncollinear spin structure occurs belowT _s . The low energy spin dynamics of La_1.65Nd_0.35CuO₄ aboveT _s are closely similar to those of stoichiometric La₂CuO₄; at 100 K the gaps for in-plane and out-of-plane polarized spin waves are 2.3 meV and 5 meV, respectively. Out-of-plane polarized magnons are little affected by the structural transition, but the gap for in-plane polarized magnons increases markedly belowT _s .     

Quantum chemical studies on the role of water microsolvation in interactions between group 12 metal species (Hg2+, Cd2+, and Zn2+) and neutral and deprotonated cysteines

Interactions of group 12 metal(II) species (Hg²⁺, Cd²⁺, Zn²⁺, Hg(H₂O) _n ²⁺ , Cd(H₂O) _n ²⁺ , and Zn(H₂O) _n ²⁺ (n?=?1, 2) with neutral (RSH), deprotonated (RS^?), and doubly deprotonated cysteine species (abbreviated as ??H₂cys??, ??Hcys^???, and ??cys^2???, respectively) are examined with the Becke three-parameter Lee?CYang?CParr (B3LYP) hybrid functional after preliminary screening in a conformation analysis with the Parameterized Model number 3 (PM3) semiempirical method. Effects of water on aqueous solution are evaluated by microsolvation and polarized continuum model (PCM) approaches. In the most stable conformations of M(H₂cys)²⁺ and M(Hcys)⁺ complexes (M?=?Hg²⁺, Cd²⁺, and Zn²⁺), the SH group of the cysteine moiety is already deprotonated and undergoes strong binding with the metal ion. Among Hg(H₂cys)²⁺ complexes, cysteine complexes of Hg²⁺ without deprotonation of the SH group and mercury(II) carboxylato-type structures are at least 83 and 117?kJ/mol less stable in energy than the most stable complex (B3LYP/6-311++G(d,p)-SDD+d+f//B3LYP/6-31G(d)-SDD+d). Although Zn²⁺ binds more strongly than Hg²⁺ to a H₂cys molecule at the high-level CCSD(T)/6-311++G(d,p)-SDD+d+f//B3LYP/6-311++G(d,p)-SDD+d+f level, [Hg(H₂O)₂]²⁺ is stronger than [Zn(H₂O)₂]²⁺ because the deformation of [Zn(H₂O)₂]²⁺ required to bind to cys is much more than in [Hg(H₂O)₂]²⁺. Complexes with a deprotonated cysteine, M(Hcys)⁺ and M(cys), prefer a multidentate structure.     

Weak ferromagnetic properties of amorphous FeGe alloys

Magnetization measurements of amorphous FeGe alloys containing 20 and 30 at.% iron have been made under high field and high pressure. These alloys possess a weakly itinerant ferromagnetic character although large inhomogeneous effects are superposed.