Soft x-ray magnetic circular dichroism study of Ca_1-xSr_xRuO_3 across the ferromagnetic quantum phase transition

TL;DR

This study uses x-ray magnetic circular dichroism to investigate the evolution of ferromagnetism in Ca_1-xSr_xRuO_3 across a quantum phase transition, revealing a Stoner-type behavior influenced by strong electron correlations.

Contribution

It provides the first detailed XMCD analysis of Ca_1-xSr_xRuO_3 across the ferromagnetic transition, highlighting the role of electron correlations in its itinerant ferromagnetism.

Findings

XMCD signals appear at x ~ 0.3 and increase with x.

Spectral line shapes remain unchanged across the transition.

Ferromagnetism shows a Stoner-type monotonic increase.

Abstract

Ca_1-xSr_xRuO_3, which is ferromagnetic for Sr concentration x > 0.3, has been studied by x-ray magnetic circular dichroism (XMCD) in Ru 3p and O 1s core-level x-ray absorption. XMCD signals appear at x ~ 0.3 and monotonically increases with x in the ferromagnetic phase. While the monotonic increase of the XMCD signals with x is of a typical Stoner-type, the absence of appreciable change in the spectral line shapes of both the Ru 3p and O 1s XMCD spectra indicate that the itinerant-electron ferromagnetism in Ca_1-xSr_xRuO_3 is influenced by strong electron correlation.