Electrical and magnetic properties of amorphous W-Mn-O films

The influence of the metal-insulator transition on the spin-glass transition in W-Mn alloys was studied by measuring the magnetic properties of W-Mn-O films as a function of oxygen content for various Mn concentrations. The metal-insulator transition was determined by the electrical resistivity of {WOx} films with 0 ? x ? 3. Contrary to the (MnSi)Ox alloys where the spin-glass transition exits in both the metallic (x ? 1) and the insulating state (1? x ? 3.6), the spin glass transition in (W-Mn)Ox alloys disappears for x ? 1.25. This disappearance does not seem to be linked directly to the metal-insulator transition, since alloys with resistivities in excess of 103 ?? cm still display a spin-glass transition, but is more likely dependent on a critical oxygen concentration which changes the host from W to WO1-1.25.