Mossbauer study of Fe/sub 0.01/Ni/sub 0.99/Cr/sub 2/S/sub 4/

Fe/sub 0.01/Ni/sub 0.99/Cr/sub 2/S/sub 4/ has been studied by Mossbauer spectroscopy and X-ray diffraction. The crystal structure is found to be monoclinic with the lattice parameters a=5.910 AA, b=3.410 AA, c=11.11 AA and beta =91.50 degrees . Magnetic hyperfine and quadrupole interactions in the antiferromagnetic state at 81 K have been studied, yielding the following results: H=156 kOe, 1/2eqQ(1+1/3 eta /sup 2/)/sup 1/2/=-2.15 mm/s, theta =59 degrees , phi =90 degrees , and eta =0.9. Electronic energy levels of Fe/sub 0.01/Ni/sub 0.99/Cr/sub 2/S/sub 4/ can be explained in terms of a Hamiltonian involving crystal field energy, spin-orbit couplings, and exchange interactions. >