Abstract
In rare-earth compounds, electric quadrupoles of 4f electrons play important roles in determining their magnetic and electric properties. Recently, we have observed modulated quadrupolar structures below TQ=0.4K in the rare-earth compound PrPb3 by means of neutron diffraction technique. In these ordered phases, interaction between quadrupoles is the RKKY-like indirect one, therefore, electric quadrupole, such as magnetic dipole moment, can play a main part which bring about variable properties.
