Interaction between superconducting and ferromagnetic order parameters in graphite-sulfur composites

Indication of superconductivity at 35 K in graphite-sulfur composites.

We report magnetization measurements performed on graphite-sulfur composites which demonstrate a clear superconducting behavior below the critical temperature T(c0) = 35 K. The Meissner-Ochsenfeld effect, screening supercurrents, and magnetization hysteresis loops characteristic of type-II superconductors were measured. The results indicate that the superconductivity occurs in a small sample fr...

First-order superconducting transition near a ferromagnetic quantum critical point.

We address the issue of how triplet superconductivity emerges in an electronic system near a ferromagnetic quantum critical point (FQCP). Previous studies found that the superconducting transition is of second order, and T(c) is strongly reduced near the FQCP due to pair-breaking effects from thermal spin fluctuations. In contrast, we demonstrate that near the FQCP, the system avoids pair-break...

Spin and charge pumping by ferromagnetic-superconductor order parameters.

We study transport in ferromagnetic-superconductor/normal-metal systems. It is shown that charge and spin currents are pumped from ferromagnetic superconductors into adjacent normal metals by adiabatic changes in the order parameters induced by external electromagnetic fields. Spin and charge pumping identify the symmetry of the superconducting order parameter, e.g., singlet pairing or triplet ...

Magnetic instabilities in superconducting composites

The stability of electric currents in multifilamentary superconducting composites against flux jumps is discussed in detail. The normal procedure for such a quantitative stability investigation is carried out. In some particular cases the stability criteria are found and analysed.

Synthesis of superconducting composites