arXiv subjects

Petra S. Häfliger

Publications and source records attributed to Petra S. Häfliger.

2 recordsLinked to original sources

arXiv2014

Oxygen isotope effect on structural parameters and on the thermal motion in La$_2$CuO$_4$

We studied the oxygen isotope effect (OIE) on the zero point motion and the thermal motion as well as on structural parameters in La$_2$CuO$_4$ by means of high-resolution neutron diffraction experiments. We found a negative OIE on the lattice parameters (-0.01%). The OIE on the isotropic thermal parameters turned out to be positive for lanthanum, copper and negative for the oxygen atoms, respectively. The Rietvield refinement of the anisotropic thermal parameters of the different directions yielded the same sign of the OIE for each ion. Our analysis shows that the OIE on isotropic thermal parameters is most pronounced for La at 15 K (up to 100%) which we found to be originating mainly from the thermal motion in x-direction as determined from the refinement of the anisotropic thermal parameters.

cond-mat.str-el↗

arXiv2007

Muon spin rotation study of the ternary noncentrosymmetric superconductors Li$_2$Pd$_x$Pt$_{3-x}$B

We investigated the superconducting state of the noncentrosymmetric superconductors Li$_2$Pd$_x$Pt$_{3-x}$B with superconducting transition temperature $T_c$= 5.16(8) K ($x$=2.25), 3.56(8) K ($x=1.5$) and 2.60 K ($x=0$) by means of muon-spin rotation ($μ$SR) and specific heat experiments. The $μ$SR relaxation rate $σ_{sc}$ was found to be constant at low temperatures for all the compounds. Data taken at different magnetic fields show that the magnetic penetration depth $λ$ is field-independent for Li$_2$Pd$_{2.25}$Pt$_{0.75}$B and Li$_2$Pt$_{3}$B. The electronic contribution to the specific heat measured in Li$_2$Pd$_{1.5}$Pt$_{1.5}$B and Li$_2$Pt$_{3}$B increases exponentially at the lowest temperatures. These features suggest that the {\it whole family} of Li$_2$Pd$_x$Pt$_{3-x}$B are single-gap s-wave superconductors across the entire doping regime.

cond-mat.supr-con↗