Hyperfine coupling constant for ⁵⁹Co estimated from a high-field susceptibility and high-field NMR shift in ferromagnetic Co₂TiGa and Co₂VGa

The hyperfine coupling constant for ⁵⁹Co in the ferromagnetic state of a Heusler alloy Co₂TiGa in the high-field range has been estimated to be 170 kOe per 1 μ_B of the moment of cobalt atom from the high-field magnetic susceptibility of 2.3 × 10^-6 emu/gOe measured at 5 K in a field range from 20 to 70 kOe and a reported positive high-field NMR shift of +0.83 percent. The value of the hyperfine coupling constant has been found to be even larger in the case of Co₂VGa. These features suggest that the positive hyperfine field at Co nucleus in the Co-based Heusler alloys is due to conduction electron polarization rather than a transferred hyperfine field.