Break-junction experiments on the zero-bias anomaly of non-magnetic and ferromagnetically ordered metals

TL;DR

This study investigates zero-bias anomalies in break junctions of non-magnetic and ferromagnetic metals, attributing them to Kondo scattering or channel switching, with results consistent across various metals and contact types.

Contribution

It provides new insights into the origin of zero-bias anomalies in atomic-scale metal contacts, linking them to Kondo effects and conductance channel switching.

Findings

Zero-bias anomalies observed in atomic-scale contacts.

Kondo temperatures range from 10 to 1000 K.

Results align with previous atomic contact studies.

Abstract

We have investigated break junctions of normal non-magnetic metals as well as ferromagnets at low temperatures. The point contacts with radii 0.15 - 15 nm showed zero-bias anomalies which can be attributed to Kondo scattering at a single Kondo impurity at the contact or to the switching of a single conducting channel. The Kondo temperatures derived from the width of the anomalies varied between 10 and 1000 K. These results agree well with literature data on atomic-size contacts of the ferromagnets as well as with spear-anvil type contacts on a wide variety of metals.