Hyperfine Fields and Electronic Structure of CsCl-Type Ternary Alloys of the First Transition Series

The ⁵⁹Co Knight shift K and the ⁵⁷Fe isomer shift have been measured in TiFe_1-xCoₓ alloys over most of the composition range 0≤x≤1. The experimental results are discussed in terms of correlations with electron concentration and s admixture in the d bands. At room temperature, K varies from a maximum of (3.2±{}0.2)% at x≈0.8, and roughly follows the electronic specific heat as the composition is varied, with a minimum of K=(0.8±0.2)% near $x=0$. K increases substantially as the temperature is lowered for x near 1, and decreases somewhat for x near 0. The maximum K measured is (4.7±{}0.2)% for x≈0.8 at 120^∘{}K. The slopes of K versus susceptibility vary from +86 kGμB per formula unit for $x=0.8$ to -47 kGμB per formula unit for $x=0.05$. The isomer-shift variation, from -0.15±{}0.01 (mm/sec relative to pure Fe) at TiFe to -0.19±{}0.02 at TiCo, is similar to that of Fe in Cr-Mn. The 47,49Ti Knight shift in TiFe is (0.26±{}0.04)% at room and at liquid-nitrogen temperatures.