PRESSURE EFFECT ON MAGNETIC EXCITATION IN THE KONDO SEMIMETAL CENISN

Effects of pressure and impurities on the magnetic excitation peak at (h) over bar omega = 4 meV are studied by neutron scattering on CeNiSn . The high pressure remarkably affects the magnetic excitation: at P = 6 kbar the excitation shifts to a higher energy region; at P = 11 kba r the excitation peak disappears below 7meV. The increase of the peak energy at 6 kbar is consistent with the explanation by the particle-ho le excitation over the hybridization gap. The sample quality, metallic or semiconducting, has no effect on the magnetic excitation spectrum.