Block magnetism coupled with local distortion in the iron-based spin-ladder compound BaFe 2 Se 3

Abstract

Magnetism in the insulating BaFe2Se3 was examined through susceptibility, specific heat, resistivity, and neutron diffraction measurements. After formation of a short-range magnetic correlation, a long-range ordering was observed below TN∼255 K. The transition is obscured by bulk properties. Magnetic moments (∥a) are arranged to form a Fe4 ferromagnetic unit, and each Fe4 stacks antiferromagnetically. This block magnetism is of the third type among magnetic structures of ferrous materials. The magnetic ordering drives unusually large distortion via magnetoelastic coupling. ©2012 American Physical Society