Dysonian Electron-Spin-Resonance Spectra of Local Magnetic Moments in Metals

TL;DR

This paper revisits Dyson's theory of electron-spin resonance in metals, emphasizing the importance of the magnetic-field prefactor for accurate spectral fitting and physical interpretation.

Contribution

It demonstrates that including the magnetic-field prefactor significantly improves the fit of Dyson's lineshape to ESR spectra, affecting the analysis of local magnetic moments in metals.

Findings

The magnetic-field prefactor impacts the accuracy of Dyson's ESR spectral fits.

Including the prefactor alters the interpretation of temperature-dependent parameters.

Revised fitting approach improves understanding of magnetic moments in metals.

Abstract

The absorptive and dispersive components of the frequency-dependent magnetic susceptibility both contribute to the electron-spin resonance (ESR) radio-frequency (rf) power absorption of local magnetic moments in metals according to Dyson's theory. The magnetic-field prefactor present in the expression for this power absorption has been omitted in the past when fitting Dyson's lineshape to the observed field derivative of broad ESR rf power absorption spectra but is shown here to significantly influence such fits and therefore also the quantitative physical interpretations of the temperature-dependent fit parameters.