Writers: Pedro Linhares C. Filho; Petrucio Barrozo; D. A. Landinez-Tellez; R. F. Jardim; W. M. Azevedo; J. Albino Aguiar
Keywords: Combustion synthesis; Ferromagnetic materials; X-ray powder diffraction; Perovskite; Manganite
Abstract: In this article, the structural and magnetic properties of the Ln2MnCoO6 (Ln=La and Dy) produced by the combustion method are reported. The samples were characterized by X-ray diffraction (XRD) with Rietveld refinement, and their magnetic properties by studying the dependence of the magnetization with the magnetic field and temperature. XRD analysis reveals that the La2MnCoO6 (LCM) consists of a mixture of crystalline orthorhombic, monoclinic, and rhombohedral phases. This mixture might be originated by the mixing of valence states of the Co+2/Mn+4 and Co+3/Mn+3. Dy2CoMnO6 (DCM) presents a mixed composition of hexagonal and orthorhombic structures with the transition metal atoms in mixed valences. Magnetic measurements show that the magnetic transition temperature TC decreases from 150 K to 85 K when the La ions are replaced by Dy. We also observe that the magnetic order changes from a ferromagnetic to a ferrimagnetic when La is replaced by Dy.