Magnetic phase diagram of the mixed-valence semiconductor TmSe under multi-extreme (P,H,T) conditions

The high-pressure (type-II) anti ferromagnetic phase of the mixed-valence semiconductor TmSe has been studied by neutron diffraction at P = 4.1 GPa in high magnetic fields. Surprisingly, the phase diagram reveals the existence, above 1.6 T, of an AF I phase reminiscent of the ambient-pressure, zero-field structure. This result provides a new opportunity to investigate the relationship between magnetic and electronic structures in Tm monochalcogenides. (c) 2005 Elsevier B.V. All rights reserved.