Magnetic and electric properties of Sr2FeMoO6

We present electrical resistivity (rho) and magnetic susceptibility (chi) d ata of the Sr2FeMoO6 double perovskite. We found that the as prepared sampl e shows semiconducting rho (T) in the whole temperature range and a magneto resistance behavior typical of electron tunneling at the grain boundaries (,gb). When the oxygen of the gb is removed rho drops one order of magnitud e. Below the magnetic ordering temperature T-C approximate to 405 K and abo ve 590 K this sample is metallic (d rho /dT > 0), while for T-C < T < 590 K we observe a weak localization. The chi (T) data follow the Curie-Weiss la w only in a short temperature range above T-C. (C) 2001 Elsevier Science BN . All rights reserved.