Mechanochemically assisted synthesis of yttrium-lanthanum orthoferrite: Structural and magnetic characterization

A.A. CRISTÓBAL; P.M. BOTTA; P.G. BERCOFF; E. F. AGLIETTI; H.R. BERTORELLO; JOSÉ M. PORTO LÓPEZ

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Año: 2010 vol. 495 p. 516 - 519

0925-8388

Polycrystalline Y0.5La0.5FeO3 powder was synthesized by mechanochemical activation of Fe3O4-La2O3-Y2O 3 reactive mixtures. X-ray diffraction was used to follow the evolution of the formation of this orthoferrite. Peaks corresponding to reactants were no longer observed after 3 h of activation, showing the completion of the reaction after this time. Magnetic hysteresis loops measured at room temperature revealed a gradual decrease of saturation magnetization, consistent with the consumption of ferrimagnetic Fe3O4 and the formation of antiferromagnetic Y0.5La0.5FeO3. However, a small ferromagnetic contribution was observed even after 3 h of milling, which can be attributed to a canting in the alignment of the two sub-lattices in the orthoferrite structure. This uncompensated antiferromagnetism disappeared when the solid was heated, giving rise to a nearly antiferromagnetic structure.