Non-collinear magnetic structure of the Sr2ErRuO6 double perovskite

The crystal and magnetic structure of Sr2ErRuO6 has been studied by means of neutron powder diffraction as well as magnetization and susceptibility measurements. Neutron diffraction profile measured at 50 K shows that the Ru5+ and Er3+ are ordered in the B-sites of the perovskite-type structure, while the Sr atoms occupy the A-site. This compound crystallizes with a monoclinic unit cell, space group P21/n and lattice parameters are approximately √2ap × √2ap × 2ap. Magnetic susceptibility measurements reveal the existence of antiferromagnetic interactions in which Ru5+ and Er3+ sublattices are involved. The field dependence of the magnetization indicates the presence of a weak ferromagnetic component at the transition temperature, arising from the spin canting of the antiferromagnetically ordered Ru5+ and Er3+ moments. Thermal evolution of the neutron diffraction patterns indicate that the Nèel temperature is 36 K and the magnetic reflections can be indexed on the basis of a propagation vector k = [0, 0, 0]. The spin arrangement is described by the AxAz magnetic modes where the Ru5+ and Er3+ moments are mainly aligned along the c-axis of the structure, forming an angle of ∼6° with the c-axis in the case of the Er3+ sublattice and ∼15° for the Ru5+ moment.