DEPENDENCE OF THE MAGNETIC-MOMENT ON THE LOCAL ATOMIC ORDER IN RH(2)MNX HEUSLER ALLOYS

The electronic structure and magnetic moment of three Rh-based Heusler alloys Rh(2)MnX, with X = Ge, Sn and Pb have been calculated using th e tight binding linear muffin-tin orbital (TB LMTO) method. The total magnetic moment increases with increasing atomic number of X. In the d ensities of states (DOS) for the ordered structure we observe a gap be tween the s band of the X atom, and the p and d bands of Rh and Mn. Th e DOS for the disordered alloys was computed using the TB LMTO-CPA met hod. For the disordered Rh-0.5(MnX)(0.25) alloy the value of the total magnetic moment was found to be smaller than for the ordered structur e.