THE CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF SRLAFESNO6 AND SRLANISBO6

The crystal and magnetic structures of the perovskite-related materials SrLaFeSnO6 and SrLaNiSbO6 have been refined using neutron diffraction data collected at room temperature and 1.7 K. SrLaFeSnO6 adopts the orthorhombic space group Pbnm with disordered Sr La and Fe Sn cations and is magnetically ordered as a G-type antiferromagnet at 1.7 K. SrLaNiSbO6 differs in that a partial order of the Ni and Sb cations results in the space group P21 n and a Type I antiferromagnetic structure. The magnetic susceptibility shows a maximum at 39 and 26 K, respectively, but there is a significant difference between the field-cooled and zero-field-cooled susceptibility above these temperatures. This effect persists to at least 250 K in SrLaFeSnO6. An explanation is developed in terms of magnetic clusters which increase in size with decreasing temperature until a long-range ordered structure is finally achieved. © 1992.