SYNTHESIS, STRUCTURE AND MAGNETIC PROPERTIES OF DISTORTED YxLa1-xFeO3: EFFECTS OF MECHANOCHEMICAL ACTIVATION AND COMPOSITION

A. A. CRISTÓBAL; P. M. BOTTA; E.F. AGLIETTI; M.S. CONCONI; P.G. BERCOFF; J. M. PORTO LÓPEZ

MATERIALS CHEMISTRY AND PHYSICS

ELSEVIER SCIENCE SA

Año: 2011 vol. 130 p. 1275 - 1279

0254-0584

The influence of the mechanochemical treatment on the synthesis and properties of        YxLa1-xFeO3 (0 £ x £ 1) orthoferrites is studied. Solid mixtures of the corresponding metal oxides were mechanically activated for several times in a high-energy ball-mill. X-ray diffraction patterns revealed that during the milling the disappearance of the reactants together with the fast conversion to orthoferrite phase takes place. Measurements of magnetization as a function of applied field showed a weak ferromagnetic behavior of the obtained materials, observing higher magnetization for larger x. The activated powders heated at 600 and 800ºC showed a progressive crystalline ordering of the orthoferrite structure together with a significant drop of magnetization. Thermal treatments at 1000ºC produced the formation of the garnet phase Y3Fe5O12 for the samples richer in yttrium, increasing the measured magnetization. Rietveld refinements of the diffraction patterns and dynamical scanning calorimetry were used respectively to determine the lattice parameters and Néel temperatures for the formed orthorferrites. The effect of the composition on the structure and magnetic behavior is discussed.