Abstract
Low-temperature magnetic susceptibilities yield an effective magnetic moment per W atom of (3.24±0.10) for both and . This value suggests a transfer of two d-shell electrons from the W to neighboring V ions to form - and - pairs along the a axis of the monoclinic low-temperature phase. Studies of the extended x-ray-absorption fine-structure pattern for various compositions of different W-cation fraction x, and of the area of the W -edge resonance as well, confirm that the valence of W is 6+. Also, examination of the position of the V K edge versus composition for these alloys and other compounds indicates that the concentration of ions increases with W-cation fraction x. Thus, upon alloying with W, the reduction in the temperature of the metal-semiconductor transition by W appears to be due to charge transfer. From x-ray small-angle scattering it was found that there are no W-atom clusters present. The high-field magnetization at low temperature suggests that alloying causes this oxide to become a spin glass.
- Received 27 August 1984
DOI:https://doi.org/10.1103/PhysRevB.31.1000
©1985 American Physical Society