NMR studies on heavy fermion and conventional metal superlattices CeCoIn5/YbCoIn5

Abstract

We performed nuclear magnetic resonance (NMR) experiments on heavy fermion and conventional metal superlattices CeCoIn[5]/YbCoIn[5]. We succeeded in identifying the signals arising from CeCoIn5 and YbCoIn[5] block layers (BLs) by comparing the spectra of the CeCoIn[5]/YbCoIn[5] superlattices, CeCoIn[5] thin film, and YbCoIn[5] thin film. Furthermore, we found that the signals of Ce-BLs could be divided into signals arising from interfacial layers and inner layers even in one Ce-BL by comparing the spectra of two CeCoIn[5]/YbCoIn[5] superlattices with different thickness of the Ce-BLs. A comparison of the spectra of the superlattices with different Ce-BL thickness and field dependence of nuclear-spin lattice relaxation rate 1/T[1] indicate that antiferromagnetic spin fluctuations at the interfacial site are more suppressed than those at the inner layer site even in the Ce-BLs.