Influence of grain-boundary defects on electric transport in CeRhSn with a non-Fermi-liquid ground state

Measurements by atomic force microscopy reported for a polycrystalline CeRhSn sample show nanometer-sized grains consisting of crystalline components. The grains are separated by a grain boundary. The high-resolution electron microscopy and secondary-ion mass spectrometry were used to determine homogeneity of the grains and the grain boundary. The grains are homogeneous up to about 60% of the major phase, with slightly off-stoichiometric phases constituting the balance, whereas the volume fractions of intercrystalline components are strongly inhomogeneous and off stoichiometric. We argue that there is possibly a ballistic transport of electrons through an interface between the grains, which strongly modifies the resistivity of the CeRhSn stoichiometric grains, which is non-Fermi-liquid in character.