Scaling of Kondo spin relaxation: Experiments on Cu-based nonlocal spin valves with Fe impurities

The relation between the Kondo spin-relaxation rate tau(-1)(sK) and the Kondo momentum-relaxation rate tau(-1)(eK) is explored by using nonlocal spin valves with submicron copper channels that contain dilute iron impurities. A linear relation between tau(-1)(sK) and tau(-1)(eK) is established under varying temperatures for any given device. Among 20 devices, however, tau(-1)(sK) remains nearly constant, despite variation of tau(-1)(eK) by a factor of 10. This surprising relation can be understood by considering spin relaxation through overlapping Kondo screening clouds and supports the physical existence of the elusive Kondo clouds.

Automated summary

A linear relationship between the Kondo spin-relaxation rate and the Kondo momentum-relaxation rate was found, where the former remains nearly constant despite a tenfold variation of the latter among 20 devices. This surprising relationship can be explained by considering spin relaxation through overlapping Kondo screening clouds, supporting the physical existence of elusive Kondo clouds.