A Comparison of the High-Frequency Magnetic Fluctuations in Insulating and Superconducting La2-xSrxCuO4

Inelastic neutron scattering performed at a spallation source is used to make absolute measurements of the dynamic susceptibility of insulating La2CuO4 and superconducting La2-xSrxCuO4 over the energy range 15<EN<350 meV. The effect of Sr doping on the magnetic excitations is to cause a large broadening in wavevector and a substantial change in the spectrum of the local spin fluctuations. Comparison of the two compositions reveals a new energy scale of 22 meV in La1.86Sr0.14CuO4.Comment: RevTex, 7 Pages, 4 postscript figure

Pressure effects on the heavy-fermion antiferromagnet CeAuSb2

The f-electron compound CeAuSb2, which crystallizes in the ZrCuSi2-type tetragonal structure, orders antiferromagnetically between 5 and 6.8 K, where the antiferromagnetic transition temperature T_N depends on the occupancy of the Au site. Here we report the electrical resistivity and heat capacity of a high-quality crystal CeAuSb2 with T_N of 6.8 K, the highest for this compound. The magnetic transition temperature is initially suppressed with pressure, but is intercepted by a new magnetic state above 2.1 GPa. The new phase shows a dome shape with pressure and coexists with another phase at pressures higher than 4.7 GPa. The electrical resistivity shows a T^2 Fermi liquids behavior in the complex magnetic state, and the residual resistivity and the T^2 resistivity coefficient increases with pressure, suggesting the possibility of a magnetic quantum critical point at a higher pressure.Comment: 5 pages, 5 firure

Dependence of nuclear magnetic moments on quark masses and limits on temporal variation of fundamental constants from atomic clock experiments

We calculate the dependence of the nuclear magnetic moments on the quark masses including the spin-spin interaction effects and obtain limits on the variation of the fine structure constant $\alpha$ and $(m_q/\Lambda_{QCD})$ using recent atomic clock experiments examining hyperfine transitions in H, Rb, Cs, Yb$^+$ and Hg$^+$ and the optical transition in H, Hg$^+$ and Yb$^+$

Evidence of Nodal Line in the Superconducting Gap Symmetry of Noncentrosymmetric ThCoC2_{2}

The newly discovered noncentrosymmetric superconductor ThCoC$_{2}$ exhibits numerous unconventional behavior in the field dependent heat capacity data. Here we present the first measurement of the gap symmetry of ThCoC$_{2}$ by muon spin rotation/relaxation $(\mu$SR) measurements. Temperature dependence of the magnetic penetration depth measured using the transverse field $\mu$SR measurement reveal the evidence of nodal pairing symmetry. To understand these findings, we carry out the calculations of superconducting pairing eigenvalue and eigenfunction symmetry due to the spin-fluctuation mechanism, by directly implemented the {\it ab-initio} band structures. We find that the system possesses a single Fermi surface with considerable three-dimensionality, and hence a strong nesting along the $k_z$-direction. Such a nesting promotes a superconducting pairing with a $\cos{k_z}$-like symmetry with a prominent nodal line on the $k_z=\pm\pi/2$ plane. The result agrees well with the experimental data.Comment: 3 pages, 5 figure

Crystal-fields in YbInNi4 determined with magnetic form factor and inelastic neutron scattering

The magnetic form factor of YbInNi4 has been determined via the flipping ratios R with polarized neutron diffraction and the scattering function S(Q,w) was measured in an inelastic neutron scattering experiment. Both experiments were performed with the aim to determine the crystal-field scheme. The magnetic form factor clearly excludes the possibility of a \Gamma7 doublet as the ground state. The inelastic neutron data exhibit two, almost equally strong peaks at 3.2 meV and 4.4 meV which points, in agreement with earlier neutron data, towards a \Gamma8 quartet ground state. Further possibilities like a quasi-quartet ground state are discussed.Comment: 7 pages, 5 figures, 2 tables, submitted to PR

Foraging ecology of ringed seals (Pusa hispida), beluga whales (Delphinapterus leucas) and narwhals (Monodon monoceros) in the Canadian High Arctic determined by stomach content and stable isotope analysis

Stomach content and stable isotope analysis (delta C-13 and delta N-15 from liver and muscle) were used to identify habitat and seasonal prey selection by ringed seals (Pusa hispida; n = 21), beluga whales (Delphinapterus leucas; n = 13) and narwhals (Monodon monoceros; n = 3) in the eastern Canadian Arctic. Arctic cod (Boreogadus saida) was the main prey item of all three species. Diet reconstruction from otoliths and stable isotope analysis revealed that while ringed seal size influenced prey selection patterns, it was variable. Prey-size selection and on-site observations found that ringed seals foraged on smaller, non-schooling cod whereas belugas and narwhals consumed larger individuals in schools. Further interspecific differences were demonstrated by delta C-13 and delta N-15 values and indicated that ringed seals consumed inshore Arctic cod compared to belugas and narwhals, which foraged to a greater extent offshore. This study investigated habitat variability and interseasonal variation in the diet of Arctic marine mammals at a local scale and adds to the sparse data sets available in the Arctic. Overall, these findings further demonstrate the critical importance of Arctic cod to Arctic food webs

Global distribution of the solar wind during solar cycle 23: ACE observations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95439/1/grl26167.pd

Tuning Low Temperature Physical Properties of CeNiGe3_{3} by Magnetic Field

We have studied the thermal, magnetic, and electrical properties of the ternary intermetallic system CeNiGe$_{3}$ by means of specific heat, magnetization, and resistivity measurements. The specific heat data, together with the anisotropic magnetic susceptibility, was analyzed on the basis of the point charge model of crystalline electric field. The $J$\,=\,5/2 multiplet of the Ce$^{3+}$ is split by the crystalline electric field (CEF) into three Kramers doublets, where the second and third doublet are separated from the first (ground state) doublet by $\Delta_{1}$ $\sim$ 100\,K and $\Delta_{2}$ $\sim$ 170\,K, respectively. In zero field CeNiGe$_{3}$ exhibits an antiferromangeic order below $T_{N}$ = 5.0\,K. For \textbf{H}\,$\parallel$\,\textbf{a} two metamagnetic transitions are clearly evidenced between 2\,$\sim$\,4\,K from the magnetization isotherm and extended down to 0.4\,K from the magnetoresistance measurements. For \textbf{H}\,$\parallel$\,\textbf{a}, $T_{N}$ shifts to lower temperature as magnetic field increases, and ultimately disappears at $H_{c}$ $\sim$ 32.5\,kOe. For $H\,>\,H_{c}$, the electrical resistivity shows the quadratic temperature dependence ($\Delta\rho = A T^{2}$). For $H \gg H_{c}$, an unconventional $T^{n}$-dependence of $\Delta\rho$ with $n > 2$ emerges, the exponent $n$ becomes larger as magnetic field increases. Although the antiferromagnetic phase transition temperature in CeNiGe$_{3}$ can be continuously suppressed to zero, it provides an example of field tuning that does not match current simple models of Quantum criticality.Comment: accepted PR