We discuss the discovery of pressure-induced antiferromagnetism in URu2Si2, in the context of neutron, NMR and µSR results. The identification of a critical pressure separating mean-field and Ising phase transitions leads us to propose that the system lies close to a bicritical point associated with magnetic and (non-magnetic) hidden order. We conclude that the recent observation of an isotropic, field-independent component in the silicon NMR line-width implies that the hidden order parameter breaks time-reversal invariance and present a preliminary discussion of the underlying nature of the hidden order parameter. Key words: URu2Si2, Hidden Order, Antiferromagnetism The origin of the entropy loss in URu2Si2 at T0 = 17.5K is an outstanding problem in heavy fermion physics. The observed staggered moment (m0 = 0.03µB) cannot account for the sharp discontinuities in bulk properties [3–8] and the entropy change that develop at this transition. Th
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.