Neutron diffraction study of the field-induced order in singlet-ground state magnet CsFeCl3

Abstract The neutron diffraction experiments have been successfully performed in the whole field region of the field-induced ordered phase in the singlet-ground state magnet CsFeCl3 for the first time. The field dependence of neutron magnetic reflection have clearly demonstrated that the field induced order is described by the order parameter 〈Sx〉. The magnetic ordering is discussed in the context of a Bose–Einstein condensation of magnetic excitations.