Nuclear spin relaxation in CoAl system

The temperature and magnetic field dependence of the nuclear spin relaxation rate $\text{1}\text{T}{}_1$ for ²⁷Al in CoAl has been investigated in the vicinity of exact stoichiometry. The experimental results are interpreted well in terms of the Benoit, de Gennes and Silhoutte (BGS) mechanism which involves a mutual flip of a nuclear spin and a localized electro spin on an excess Co atom via the Rudermann, Kittel, Kasuya and Yosida (RKKY) interaction, as well as the Korringa mechanism. The dynamic behavior of the localized moments thus obtained is discussed in terms of the Kondo effect.