We report the results of a (Formula presented) nuclear magnetic resonance (NMR) study of (Formula presented) near the ordered composition with (Formula presented) at temperatures between 4 and 500 K. All compositions are found to be metallic or semimetallic, though electrical resistivity has indicated a metal-insulator transition at (Formula presented) The low-temperature NMR relaxation rates for stoichiometric (Formula presented) and nonstoichiometric (Formula presented) and (Formula presented) compounds follow a Korringa law, associated with a finite density of carriers at the Fermi level. High-temperature relaxation rates for (Formula presented) go over to a semiconductorlike activated form, providing information about the gap structure near the Fermi energy. The results are consistent with pseudogap features identified by recent band-structure calculations, although with smaller energy splittings. We analyze pseudogap changes vs composition, and compare the band-filling behavior to a recent coherent potential approximation calculation.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2000|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics