Crystal and magnetic structure of the perovskites La2MTiO6 (M = Co, Ni)

Abstract

The crystal structures of the perovskites La₂MTiO₆ (M = Co and Ni) were determined on the basis of powder neutron diffraction data collected at room temperature. Refinements of the data showed that these compounds have monoclinic symmetry, space group P2₁/n, and the common structure is a perovskite-type with a partially ordered arrangement of M(II) and Ti(IV) cations on the 6-coordination sites.

Magnetic structures of type II have been determined from neutron diffraction data collected at 1.5 K and it was found that there was a long range antiferromagnetic ordering where only the M²⁺ ions are responsible for their magnetic properties. The antiferromagnetic ordering is explained by means of a propagation vector [k = ½, 0, ½] and the respective magnetic moments at 1.5 K are 2.88 μ_B for Co and 2.05 μ_B for Ni.