Neutron scattering experiments for the study of in-plane ordered moment in URuSi

Metoki, Naoto   ; Sakai, Hironori   ; Yamamoto, Etsuji  ; Tateiwa, Naoyuki   ; Matsuda, Tatsuma; Haga, Yoshinori   

The hidden order parameter in URuSi remains an open question for this quarter of a century. Many type of models have been proposed. The models predict unusual order parameters such as higher order multipole, dynamical origin, or very recently, "hastatic" order, accompanying Ising quasi-particles. We provide neutron scattering data measured at the wave vector =(003) for the in-plane magnetic component. The existence of the in-plane component in the order of 0.01 or 1010 Bohr magneton has been proposed by a recent theoretical studies. The data were obtained also under magnetic field up to 10 T along the [010] direction in order to reveal a possible type antiferro-quadrupole (AFQ) order at the propagation of =(001) proposed previously. Our data indicate that there is no in-plane magnetic component within the experimental accuracy of 0.004 Bohr magneton. Namely we could not obtain the results which support these theories.