MOSSBAUER STUDIES OF YTI(FE1-XMX)11 (M = CO AND NI)

Fe-57 Mossbauer spectra of YTi(Fe(1-x)M(x)11 (M = Co and Ni) have been studied. The average isomer shifts increase monotonically. The average quadrupole splittings have a sudden change for YTi(Fe(1-x)Co(x))11 between x = 0.4 and 0.6. It appears that a spin reorientation occurs over this composition range. Both hyperfine fields for the three sites and the average field increase at first, and then decrease with increasing Co or Ni concentration. The maximum of the average hyperfine field is 27.7 T at x = 0.6 for YTi(Fe(1-x)Co(x))11 and 24.1 T at about x = 0.2 for YTi(Fe(1-x)Ni(x))11. The average moments of Co and Ni atoms are 1.3(1)mu-B and 0.6(1)mu-B, respectively, obtained from the formula mu = (1 - x)mu-Fe + x-mu-T.