Physical properties of disordered double-perovskite Ca2-xLa xFeIrO6

Abstract

In this work we have synthesized polycrystalline samples for the series of double-perovskite Ca2-x Lax FeIr O6. Their structural and magnetic properties were investigated using experiments of magnetic susceptibility and x-ray powder diffraction. The Ca2-x Lax FeIr O6 compounds form in a monoclinic structure, space group P21n, with the presence of significant FeIr cationic disorder. Interestingly, our results indicate a change in the nature of the microscopic magnetic interaction induced by La doping, where the system seems to evolve from antiferromagnetic in the extremities of the series, x=0 (TN ≈75 K) and x=2.0, to ferrimagnetic in intermediate regions of the series. However, due to significant presence of disorder and strong competition between ferromagnetic and antiferromagnetic interactions, the saturation of the magnetization was not found to be larger than 0.1 μB Fe. © 2008 American Institute of Physics.