Enhanced magnetoresistance in the Ruddlesden-Popper compound Sr3Fe1.5Co0.5O6.67

We report the synthesis of the Ruddlesden-Popper material Sr3Fe1.5Co0.5O6.67 (a compound usually obtained under high-pressure conditions) by a simpler normal pressure liquid-mix method and its structural characterization by means of X-ray powder diffraction. In this material-which is semiconducting and shows a glassy magnetic behavior-the combination of the reduced dimensionality of the structure compared to 3D perovskites, the small grain size obtained by our synthesis method and the selected stoichiometry, results in a record magneto resistance in these kind of compounds, -47% at T = 5 K and H = 50 kOe, that is explained on the basis of intragranular and intergranular effects. (C) 2003 Elsevier Science B.V. All rights reserved.