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

Abstract

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 μB 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.