Characterizing a high spin magnetic impurity via Andreev reflection spectroscopy

The ground state properties of a high spin magnetic impurity and its interaction with an electronic spin are probed via Andreev reflection. We see that through the charge and spin conductance one can effectively estimate the interaction strength, the ground state spin and magnetic moment of any high spin magnetic impurity. We show how a high spin magnetic impurity at the junction between a normal metal and superconductor can contribute to superconducting spintronics applications. Particularly, while spin conductance is absent below the gap for Ferromagnet-Insulator-Superconductor junctions we show that in the case of a Normal metal-High spin magnetic impurity-Normal Metal-Insulator-Superconductor (NMNIS) junction it is present. Further, it is seen that pure spin conduction can exist without any accompanying charge conduction in the NMNIS junction.Comment: 19 pages, 13 Figures, accepted for publication in The European Physical Journal

Honing in on a topological zero-bias conductance peak

A popular signature of Majorana bound states in topological superconductors is the zero-energy conductance peak with a height of $2e^2/h$. However, a similar zero energy conductance peak with almost the same height can also arise due to non-topological reasons. Here we show that these trivial and topological zero energy conductance peaks can be distinguished via the zero energy local density of states and local magnetization density of states. We find that the zero-energy local density of states exhibits oscillations with a finite period for a trivial zero-bias conductance peak. In contrast, these oscillations disappear for the topological zero-bias conductance peak. On the other hand, zero energy local magnetization density of states shows a periodic oscillation for trivial zero-bias conductance peak, while for topological ZBCP, they vanish. Our results suggest that zero-energy local density of states and local magnetization density of states can be used as an experimental probe to distinguish trivial zero energy conductance peak from topological zero energy conductance peak.Comment: 7 pages, 5 figure

Quantized Josephson phase battery

A ferromagnetic Josephson junction with a spin-flipper (magnetic impurity) sandwiched in-between acts as a phase battery that can store quantized amounts of superconducting phase difference $\Phi_0$ in the ground state of the junction. Moreover, for such $\Phi_0$-Josephson junction anomalous Josephson current appears at zero phase difference. We study the properties of this quantum spin-flip scattering induced anomalous Josephson current, especially its tun-ability via misorientation angle between two Ferromagnets.Comment: 11 pages (with supplementary material), 9 figures, accepted for publication in EPL (Euro Physics Letters