SITE SELECTIVITIES AND MAGNETIC-MOMENTS OF V, CR, AND MN DOPED IN GAMMA-TIAL ALLOYS

Magnetic and x-ray diffraction measurements on the system (Ti50Al50)10 0-xMx (M = V, Cr) are used to determine, respectively, the magnetic mo ment (associated with the dopants M) and changes in the lattice parame ters. In addition, site selectivity by the dopants between the Ti and Al sites in the L10 structure is determined by measuring the changes w ith x (x = 0.12, 0.33, 0.71, and 1.21 at. % for V and x = 0.17, 0.41, 0.88, 1.14, and 1.91 at. % for Cr) the intensities of the (001) and (1 10) superlattice peaks. These results are compared with our earlier st udies of the Mn-doped system that showed that the Mn substitutes for T i and carries a moment of 2.3 mu(B)/Mn atom. For V and Cr dopings, mu/ atom decreases as x increases, the largest values being 1.01 mu(B)/V a nd 0.55 mu(B)/Cr at the lowest dopings. At the lowest x, V and Cr occu py the Ti sites, but for higher dopings, Ti and Al sites are occupied with about equal probability and mu approaches constant magnitudes of about 0.3 mu(B). These results suggest that only Ti occupancy results in a localized moment on the dopant. For Mn and V dopings, the magnitu des of the moments are in good agreement with a recent calculation of Khowash et al.