Exotic magnetism below TN17.5 K is studied within the level scheme where the lowest multiplet is a doublet within the 5f2 configuration. Effective g-factors of pseudo-spins with S = ½, which describe the degree of freedom of the doublet, are highly anisotropic: gx = gy = 0 for the xy-components and gz0 for the z-component. It is proposed that a recently discovered transition of first order at a critical pressure pc1.5 GPa is that between an ordered state of quadrupoles, with order parameter O(x2)-y2 or Oxy, below pc and an ordered state of dipoles, with order parameter Oz, above pc; pseudo-spins are ordered within the xy-plane below pc, and they are along the z-axis above pc. The proposal of this scenario is followed by many predictions. No static magnetic moments exist below pc. The anisotropy of Van Vleck's susceptibility within the xy-plane is of twofold symmetry corresponding to O(x2)-y2 or Oxy. What one observes by means of neutron diffraction and µSR (muon spin resonance) below pc are dynamically but slowly fluctuating magnetic moments. The softening of magnons occurs with pressures approaching pc below pc. Although static magnetic moments exist above pc, no magnon excitations can be observed there.
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