  Magnetic frustration, which is well-defined in insulating systems with
localized magnetic moments, yields exotic ground states like spin ices, spin
glasses, or spin liquids. In metals magnetic frustration is less well defined
because of the incipient delocalization of magnetic moments by the interaction
with conduction electrons, viz., the Kondo effect. Hence, the Kondo effect and
magnetic frustration are antithetic phenomena. Here we present experimental
data of electrical resistivity, magnetization, specific heat and neutron
diffraction on CePdAl, which is one of the rare examples of a geometrically
frustrated Kondo lattice, demonstrating that the combination of Kondo effect
and magnetic frustration leads to an unusual ground state.
