MAGNETIC X-RAY-SCATTERING STUDY OF URANIUM ARSENIDE

The resonant magnetic x-ray scattering in UAs has been measured from 3.4 to 5.0 keV through the MIII, MIV, and MV absorption edges. The data are fit by three dipole oscillators that add coherently. The polarization dependence of nonresonant magnetic scattering was measured at 7.6 keV in the type-IA 2q phase below T=63 K. The ratio of the (0,1/2,2)- magnetic reflection to the (0,0,2)- charge reflection is 1×10-9, and the ratio calculated assuming the free-ion values of L=6 and S=3/2 is 1.04×10-9. This is a direct measurement of the strong orbital contribution to the magnetic moment in UAs. In the type-IA phase a tetragonal lattice distortion with c/a=1.0002 and a (003)- charge peak associated with a charge modulation at 2, where is the modulation wave vector of the magnetic structure, were observed. © 1990 The American Physical Society.