Effect of pressure on the Electron Spin Resonance of a Heavy-Fermion metal

TL;DR

This study explores how hydrostatic and chemical pressures influence the electron spin resonance in the heavy-fermion metal YbRh2Si2, revealing pressure-dependent changes in ESR parameters linked to electron hybridization and disorder effects.

Contribution

It provides new insights into the pressure dependence of ESR in heavy-fermion systems, highlighting the local character of Yb3+ resonance under varying pressure conditions.

Findings

Pressure reduces hybridization, altering ESR g factor and line width.

Internal pressure via Co doping introduces disorder effects.

ESR behavior under pressure reflects the local nature of Yb3+ ions.

Abstract

We investigate the electron-spin resonance (ESR) phenomenon in the heavy-fermion metal YbRh2Si2 by applying hydrostatic pressure up to 3 GPa and by inducing internal pressure on the Yb site chemically in Yb(Rh1-xCox)2Si2 samples. We found that the increase in pressure, reducing the hybridization between 4f and conduction electrons, leads to a remarkable change in the temperature dependence of the g factor and broadens the ESR line. We relate the differences between the effect of internal and external pressure on the low temperature ESR parameters to the disorder induced by Co doping. The pressure effects on the Yb3+ related resonance in YbRh2Si2 again manifest its local character when compared with the resonance of diluted Gd in heavy-fermion metals.