Absence of local magnetic moments in Ru and Rh impurities and clusters on Ag(100) and Pt(997)

TL;DR

This study used x-ray magnetic circular dichroism to show that Ru and Rh impurities and clusters on Ag(100) and Pt(997) do not exhibit detectable local magnetic moments at low temperatures, challenging theoretical expectations.

Contribution

It provides the first experimental evidence that Ru and Rh on nonmagnetic metal surfaces lack detectable magnetic moments, contradicting prior theoretical predictions.

Findings

No dichroic signal detected at Ru and Rh edges at low temperature.

Magnetic moments are below 0.04 μB per atom for all studied coverages.

Results challenge existing theoretical models of magnetism in these systems.

Abstract

The magnetism of quench-condensed Ru and Rh impurities and metal films on Ag(100) and Pt(997) has been studied using x-ray magnetic circular dichroism. In the coverage range between 0.22 ML and 2.0 ML no dichroic signal was detected at the M3,2 absorption edges of Ru on Ag(100) at a temperature of 5 K in the presence of an applied magnetic field. The same was found for coverages between 0.12 ML and 0.5 ML of Rh on Ag(100) and Pt(997). It is concluded that the magnetic moments of single impurities, small clusters of various shape and monolayers of the 4d metals are below the detection limit of 0.04 muB per atom. These results provide an unambiguous determination of the local magnetic moment of Ru and Rh deposited on nonmagnetic transition-metal surfaces, which are in contrast with theoretical predictions.