Summary

We measured NMR spectra on CaB₆ and LaB₆ and did not find any unexpected effects; we can say that, concerning NMR, the static properties of our samples are well understood.

Then we investigated the spin-lattice relaxation rate 1/T₁ in SrB₆ and CaB₆ and found very surprising and unexpected features which are shown to be an intrinsic property of the complex electronic structure of SrB₆ and CaB₆. Up to now there is no model which explains the temperature dependence of 1/T₁.

We have shown that SrB₆ and CaB₆ have very similar properties and that the slight La-doping in Ca_1-xLa_xB₆ seems not to influence the the NMR response.