Scaling of the magnetic entropy and magnetization in YbRh_2(Si_{0.95}Ge_{0.05})_2

TL;DR

This study investigates the magnetic entropy and magnetization scaling in a Ge-doped YbRh_2Si_2 compound near its quantum critical point, revealing disintegration of heavy quasiparticles and consistent quantum-critical fluctuations.

Contribution

It provides the first detailed analysis of the magnetic entropy and magnetization scaling behavior at the quantum critical point in YbRh_2(Si_{0.95}Ge_{0.05})_2, demonstrating the disintegration of heavy quasiparticles.

Findings

Unique temperature over magnetic field scaling observed.

Field dependence of entropy matches temperature dependence of magnetization.

Quantum-critical fluctuations influence thermal and magnetic properties coherently.

Abstract

The magnetic entropy of YbRh_2(Si_{0.95}Ge_{0.05})_2 is derived from low-temperature ($T\geq 18$ mK) specific heat measurements. Upon field-tuning the system to its antiferromagnetic quantum critical point unique temperature over magnetic field scaling is observed indicating the disintegration of heavy quasiparticles. The field dependence of the entropy equals the temperature dependence of the dc-magnetization as expected from the Maxwell relation. This proves that the quantum-critical fluctuations affect the thermal and magnetic properties in a consistent way.