Zero-field hyperfine spectra of Tb-159 in polycrystalline samples of T
bMn6Sn6 and TbMn6Ge6 have been measured by NMR at 4.2 K. In TbMn6Sn6 t
he transferred hyperfine field from the transition-metal sublattice is
found to be approximately 24 T. The principal component gamma(N)V(cc)
of the electric-field gradient is approximately 3.2 X 10(21) V m(-2).
The spectrum of TbMn6Ge6 is similar to that of the stannide.