Magnetic properties, hyperfine interactions, and spin dynamics of rare earth–beryllium intermetallic compounds

Measurements of lattice parameter, magnetic susceptibility, and 9Be nuclear magnetic resonance and relaxation were performed in a series of rare-earth–beryllium intermetallic compounds REBe13 (RE = La, Cc, Nd, Gd). The anomalous results in CeBe13 can be inter-preted in terms of the presence of variable concentrations of Ce3+ and Ce4+ ions in the sample with a lifetime of the order of 10−13 s. In NdBe13 it is found that crystal field effects are important in the temperature range investigated and they preclude magnetic order down to 1.5°K. GdBe13 becomes ferromagnetic at about 22°K but the magnetic susceptibility is anomalous below about 100°K. Both in NdBe13 and GdBe13 the 9Be asymmetric NMR spectrum at high temperature can be explained by considering only the magnetic dipolar interaction of the nuclei with the paramagnetic moments while the isotropic part of the shift is small and negative. From the 9Be spin–lattice relaxation at high temperature reasonable values for the electronic exchange coupling parameter are obtained.