Magnetoresistance of Fe-Ta-O films prepared by RF plasma jet method

The structure, magnetic and electric properties of Fe-Ta-O films prepared b y the RF plasma jet technique were investigated. With increasing content of O the conductance changes from metallic to tunnelling one. In some films w ith the Fe/Ta ratio close to 0.25 the superparamagnetic properties and spin -dependent tunnelling magneto resistance (with Delta rho/rho up to 1.5% at 77.3 K) were observed. The behavior can be explained by the nanogranular st ructure consisting of ferromagnetic metallic grains embedded in an insulati ng amorphous matrix. (C) 2001 Elsevier Science B.V. All rights reserved.