arXiv subjects

J. D. Thompson

Publications and source records attributed to J. D. Thompson.

291 records · Page 17Linked to original sources

arXiv1999

Low-Field Anomaly in the Specific Heat of s-wave Superconductors due to the Expansion of the Vortex Cores

The magnetic field dependence of the electronic specific heat C(H) in the s-wave superconductor NbSe_2 shows curvature at low fields, resembling the near H^1/2 term in C(H) which has been reported in high-T_c superconductors and attributed to a d-wave pairing state. In NbSe_2 we find that the low field behavior in C(H) is described quantitatively by the expansion of vortex cores and the field dependence of the magnetic induction B above H_c1. The associated change in the density of quasiparticle states localized in the vortex cores provides a simple explanation for the "low-field anomaly" in C(H) observed in s-wave superconductors.

cond-mat.supr-con↗

arXiv1999

Disorder-Driven Non-Fermi-Liquid Behavior in CeRhRuSi_2

We report measurements of the bulk magnetic susceptibility and ^{29}Si nuclear magnetic resonance (NMR) linewidth in the heavy-fermion alloy CeRhRuSi_2. The linewidth increases rapidly with decreasing temperature and reaches large values at low temperatures, which strongly suggests the wide distributions of local susceptibilities χ_j obtained in disorder-driven theories of non-Fermi-liquid (NFL) behavior. The NMR linewidths agree well with distribution functions P(χ) which fit bulk susceptibility and specific heat data. The apparent return to Fermi-liquid behavior observed below 1 K is manifested in the vanishing of P(χ) as χ\to \infty, suggesting the absence of strong magnetic response at low energies. Our results indicate the need for an extension of some current theories of disorder-driven NFL behavior in order to incorporate this low-temperature crossover.

cond-mat.str-el↗

arXiv1998

Suppression of Antiferromagnetic Order by Light Hole Doping in La_2Cu_{1-x}Li_xO_4: A ^{139}La NQR Study

^{139}La nuclear quadrupole resonance measurements in lightly doped La_2Cu_{1-x}Li_xO_4 have been performed to reveal the dependence of the magnetic properties of the antiferromagnetic CuO_2 planes on the character of the doped holes and their interactions with the dopant. A detailed study shows that the magnetic properties are remarkably insensitive to the character of the dopant impurity. This indicates that the added holes form previously unrecognized collective structures.

cond-mat.str-el↗