Magnetic Excitations In U(Ru1-Xrhx)(2)Si-2 (X <= 0.03)

We have investigated magnetic excitations for a mixed phase of hidden order (HO) and the anti ferromagnetic (AF) order in U(Ru1-xRhx)(2)Si-2 (x <= 0.03) by means of inelastic neutron scattering. The inelastic peaks observed at Q = (1, 0, 0) and (1,0.4,0) in the HO phase for x = 0 and 0.015 at 1.4 K are found to be strongly reduced in the AF dominant compositions of x = 0.02 and 0.03. Similar behavior is observed as the HO is replaced by the AF order upon cooling for x = 0.02. The x-T region in which the strong reduction of inelastic peaks is observed corresponds to the AF-rich region, indicating that the magnetic excitations typical for the HO-phase vanish in the AF phase. (c) 2005 Published by Elsevier B.V.