Spin Fluctuation and Crystal Field Excitation of a Heavy Fermion Compound YbAgGe studied by Inelastic Neutron Scattering

Inelastic neutron scattering experiment has been performed on a new heavy fermion compound YbAgGe for a polycrystalline sample at zero magnetic field. A quasielastic scattering and a crystal field excitation at 12 meV was observed. Both of them are broadened with an intrinsic width of 0.9 meV at 1.5 K which increases to about 3 meV at 300 K. The temperature dependence follows Gamma_0+AT^(1/2) typically observed in Kondo systems. Crystal field parameters were also deduced. To explain the result that only one excitation isobserved at 12 meV, it is concluded that the B22 term should be the main component.