J. Phys. IV France 09 (1999) Pr10-383-Pr10-385
Observation of a metallic resistivity behavior below 60 K in annealed molybdenum blue bronzesJ. Richard1, B. Zawilski1, J. Marcus2 and J. Dumas2
1 Centre de Recherches sur les Très Basses Températures, CNRS, BP. 166, 38042 Grenoble cedex, France
2 Laboratoire d'Études des Propriétés Électriques des Solides, CNRS, BP. 166, 38042 Grenoble cedex, France
When annealing molybdenum blue bronzes in the presence of a metal (Ag or Cu) a metallic resistivity behavior is observed below T ≈ 60 K in the three crystal directions. Nevertheless, DC conductivity and dielectric constant measurements still clearly exhibit the presence of a charge density wave (CDW). Electronic Paramagnetic Resonance (EPR) studies of annealed samples revealed a high concentration of Mo5+ sites with respect to untreated samples suggesting that due to some chemical reactions between the metal and the blue bronze some Mo6+ sites have been change into Mo5+ sites. We have discussed possible interpretations of such anomaly.
© EDP Sciences 1999