Characterizing a high spin magnetic impurity via Andreev reflection spectroscopy

TL;DR

This paper investigates how Andreev reflection spectroscopy can be used to characterize high spin magnetic impurities, revealing their interaction strength, ground state spin, and magnetic moment, with implications for superconducting spintronics.

Contribution

It introduces a method to estimate properties of high spin magnetic impurities using conductance measurements and explores their role in superconducting spintronics devices.

Findings

Charge and spin conductance can estimate impurity properties.

High spin impurities enable pure spin conduction without charge flow.

Spin conductance differs significantly in NMNIS junctions compared to ferromagnet-insulator-superconductor junctions.

Abstract

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.