J. T. Markert | Searcharxiv

arXiv2001

Superconductivity and Spin Fluctuations in the Electron-Doped Infinitely-Layered High Tc Superconductor Sr$_0.9$La$_0.1$CuO$_2$ (Tc=42K)

This paper describes the first 63-Cu NMR study of an electron-doped infinitely-layered high Tc superconductor Sr$_0.9$La$_0.1$CuO$_2$ (Tc=42K). The spin dynamics in the normal state above Tc exhibits qualitatively the same behavior as some hole-doped materials with significantly enhanced spin fluctuations. Below Tc, we observed no signature of a Hebel-Slichter coherence peak, suggesting an unconventional nature of the symmetry of the superconducting order parameter.

cond-mat.supr-con↗

arXiv1995

Reproducible noise in a macroscopic system: magnetic avalanches in Perminvar

A study of magnetic avalanches in Perminvar, an Fe-Ni-Co alloy, shows that some avalanches are almost exactly reproducible from one magnetic field cycle to the next, while others show significant variability. Averaging over many cycles produces a fingerprint reflecting the reproducibility of the noise. The fingerprint is not strongly temperature or driving-rate dependent, indicating that the variability is a consequence of dynamical effects. We also find that the slope of the cycle-averaged magnetization, d /dH, is correlated with the cycle-to-cycle variations in magnetization, suggesting an analogy with the fluctuation-dissipation relationship from equilibrium thermodynamics.

adap-org↗