Magnetic and superconducting properties on S-type single-crystal CeCu2_2Si2_2 probed by 63^{63}Cu nuclear magnetic resonance and nuclear quadrupole resonance

We have performed $^{63}$Cu nuclear magnetic resonance/nuclear quadrupole resonance measurements to investigate the magnetic and superconducting (SC) properties on a "superconductivity dominant" ($S$-type) single crystal of CeCu$_2$Si$_2$. Although the development of antiferromagnetic (AFM) fluctuations down to 1~K indicated that the AFM criticality was close, Korringa behavior was observed below 0.8~K, and no magnetic anomaly was observed above $T_{\rm c} \sim$ 0.6 K. These behaviors were expected in $S$-type CeCu$_2$Si$_2$. The temperature dependence of the nuclear spin-lattice relaxation rate $1/T_1$ at zero field was almost identical to that in the previous polycrystalline samples down to 130~mK, but the temperature dependence deviated downward below 120~mK. In fact, $1/T_1$ in the SC state could be fitted with the two-gap $s_{\pm}$-wave rather than the two-gap $s_{++}$-wave model down to 90~mK. Under magnetic fields, the spin susceptibility in both directions clearly decreased below $T_{\rm c}$, indicative of the formation of spin singlet pairing. The residual part of the spin susceptibility was understood by the field-induced residual density of states evaluated from $1/T_1T$, which was ascribed to the effect of the vortex cores. No magnetic anomaly was observed above the upper critical field $H_{c2}$, but the development of AFM fluctuations was observed, indicating that superconductivity was realized in strong AFM fluctuations.Comment: 10 pages, 8 figure

c-axis Raman Scattering in MgB2: Observation of a Dirty-Limit Gap in the pi-bands

Raman scattering spectra from the ac-face of thick MgB2 single crystals were measured in zz, xz and xx polarisations. In zz and xz polarisations a threshold at around 29 cm^{-1} forms in the below Tc continuum but no pair-breaking peak is seen, in contrast to the sharp pair-breaking peak at around 100 cm^{-1} seen in xx polarisation. The zz and xz spectra are consistent with Raman scattering from a dirty superconductor while the sharp peak in the xx spectra argues for a clean system. Analysis of the spectra resolves this contradiction, placing the larger and smaller gap magnitudes in the sigma and pi bands, and indicating that relatively strong impurity scattering is restricted to the pi bands.Comment: Revised manuscript accepted for publication in Physical Review Letter

Enhancement of soft x-ray emission using prepulses with 2ω and 4ω laser plasmas

Copyright 1988 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 63(5), 1787-1789, 1988 and may be found at http://dx.doi.org/10.1063/1.33992

Energy transport in aluminum targets irradiated by a 263-nm laser

Copyright 1988 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 52(10), 786-788, 1988 and may be found at http://dx.doi.org/10.1063/1.9928

Measurements of mass ablation rate and pressure in planar targets irradiated by 0.27-μm laser light

Copyright 1986 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 60(11), 3840-3844, 1986 and may be found at http://dx.doi.org/10.1063/1.33755

Experimental study of energy transport in thin Al and Au foils irradiated with a 263-nm laser

Copyright 1989 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 65(12), 5068-5071, 1989 and may be found at http://dx.doi.org/10.1063/1.34318

Enhancement of keV x-ray emission in laser-produced plasmas by a weak prepulse laser

Copyright 1987 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 50(12), 720-722, 1987 and may be found at http://dx.doi.org/10.1063/1.9807