Electrical resistivity dip in SbxVyMozOt phases

Electrical resistivity dips have been discovered in the temperature range 100-500 K both in the SbVO4.96 matrix and the SbxVyMozOt phases for 10 mol% solubility of MoO3 in SbVO5. As the Sb content increases and simultaneously the V content decreases, the value of the resistivity at the dip, rho d, decreases and shifts the dip to higher temperatures. The magnetic measurements showed a spontaneous magnetization and parasitic magnetism of the solid solutions under study. Characteristic for parasitic magnetism is a small value of the magnetic moment, here 0.014 mu(B)/f.u. at 4.2 K and at a magnetic field of 14 T as well as a small value of the mass susceptibility, here 10(-5) cm(3)/g. The value of the Neel temperature, T-N <= 8 K, and the Curie-Weiss temperature, theta(CW) <= -208 K, indicate a collinear antiferromagnetic (AFM) order. We suggest that neither the magnetism nor the Mo-content can be correlated with the resistivity anomalies. Therefore, these effects may rather be interpreted in terms of a small-polaron gas in the resistivity dip area. Alternatively, they could mark a lattice/electronic entropy-driven incomplete metal-insulator transition.