Annealing effect on the reduction of Fermi-level density of states in CoTiSb: NMR evidence
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
80
Journal Issue
17
Pages
174202-1 - 174202-6
Date Issued
2009
Author(s)
Abstract
With the aim to examine the variation in the electronic properties of CoTiSb due to heat treatment, a comparative study of the as-cast and annealed samples using C 59 o nuclear magnetic resonance (NMR) spectroscopy was performed. All NMR observations clearly indicate a significant change in the local electronic characteristics for the annealed sample. The spin-lattice relaxation rate measurements further provide an estimate of Co-d Fermi-level density of states, Nd (EF), indicating a substantial reduction in Nd (EF) for the specimen with heat treatment. This finding gives a microscopic interpretation for the larger electrical resistivity and Seebeck coefficient in the annealed half-Heusler alloys, as the samples with higher electrical resistivity and Seebeck coefficient usually are associated with lower carrier densities in the vicinity of the Fermi level. © 2009 The American Physical Society.
Type
journal article