  We present an experimental study of the magnetic structure and dynamics of
two frustrated hyperkagome compounds, Gd3Ga5O12 and Gd3Al5O12. It has
previously been shown that Gd3Ga5O12 exhibits long-range correlations of
multipolar directors, that are formed from antiferromagnetic spins on loops of
ten ions. Using neutron diffraction and Reverse Monte Carlo simulations we
prove the existence of similar magnetic correlations in Gd3Al5O12, showing the
ubiquity of these complex structures in frustrated hyperkagome materials.
  Using inelastic neutron scattering we shed further light on the director
state and the associated low lying magnetic excitations. In addition we have
measured quasielastic dynamics that show evidence of spin diffusion. Finally,
we present AC susceptibility measurements on both Gd3Ga5O12 and Gd3Al5O12,
revealing a large difference in the low frequency dynamics between the two
otherwise similar compounds.
