Abstract
The effective magnetic fields at all non-Mn sites, the nuclear-hyperfine contributions to the specific heat, and the paramagnetic Curie temperatures have been calculated for the Heusler alloys MnAl, MnIn, and MnSn, by an extension of the virtual-bound-state (resonance) model previously used by Caroli and Blandin. The required electronic factors are determined from paramagnetic-susceptibility and Knight-shift data on dilute Cu-base binary alloys; and a phenomenological procedure is used to estimate the reduction in factors appropriate for the corresponding ions in the Heusler alloys. The latter effect is important, and failure to take the reduced -wave character into account yields hyperfine fields which are too large by a factor of 2-4 for the polyvalent ions. Our predictions for those saturation hyperfine fields which have not yet been determined are -355±45 KOe for In in MnIn, and -280±45 and -260±100 kOe for Cu and Sn, respectively, in MnSn. The nuclear-hyperfine contribution to the specific heat of MnIn is predicted to be . We give a critical and comprehensive comparison of theoretical results and available experimental data.
- Received 24 November 1969
DOI:https://doi.org/10.1103/PhysRevB.1.3101
©1970 American Physical Society