Synthesis, structure and magnetic properties of distorted YxLa1−xFeO3: Effects of mechanochemical activation and composition

The influence of mechanochemical treatment on the synthesis and properties of YxLa1−xFeO3 (0 ≤ x ≤ 1) orthoferrites is studied. Solid mixtures of the corresponding metal oxides were treated in a high-energy ball-mill. X-ray diffraction revealed that during the milling the disappearance of the reactants and a fast conversion to orthoferrite phase take place. Magnetic measurements showed a weak ferromagnetic behavior of the obtained materials, observing higher magnetization for larger x. The activated powders heated at 600 and 800 °C showed a progressive crystalline ordering together with a significant drop of magnetization. Thermal treatments at 1000 °C produced the formation of the phase Y3Fe5O12 for the samples richer in yttrium, increasing the 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 orthoferrites. The effect of the composition on the structure and magnetic behavior is discussed.