High-pressure synthesis, structural and complex magnetic properties of the ordered double perovskite Pb_2NiReO_6

摘要

The ordered double perovskite Pb_2NiReO_6 has been prepared at 6 GPa and temperatures ranging from 1273 to 1373 K. Its crystal structure determined by X-ray powder diffraction and selected area electron diffraction shows monoclinic symmetry with centrosymmetric space group I2/m (a = 5.6021(1) ?, b = 5.6235(1) ?, c = 7.9286(1) ? and β = 90.284°(1)). High angle annular dark field microscopy studies reveal the existence of compositional microdomains. The compound displays a re-entrant spin-glass transition from a ferrimagnetic ordering below T_N ~ 37 K between the Re~(+5) and Ni~(+3) (high spin configuration) magnetic sublattices to a spin-glass configuration. Magnetic field dependent magnetization measurements revealed wasp-waisted hysteresis loops at 5 K. These shaped features originate from the antiferromagnetic/ferromagnetic (AFM/FM) competing interactions.