Journal or Book Title
Physical Review B
The antiferromagnetic energy gap and optical properties of single crystals of Cr and of Cr alloyed with 0.45, 0.94, 2.5, and 4.5% Mn and with 1.05 and 2.0% Re have been investigated by measuring the optical absorption over a photon energy range of 0.08-5 eV. The data were taken at 4.2 K by a calorimetric technique. It is found that at 4.2 K, approximately 1% Mn or Re will cause commensurate antiferromagnetic ordering, and the energy gap shifts abruptly from 0.13 to 0.36 eV near this concentration of diluent. Evidence is given for indirect transitions occurring across a double energy gap in the noncommensurate samples, and the results are explained in terms of a band model. The widths of the absorption peak and the peak in ε2 in the commensurate samples are discussed in terms of a gap anisotropy and impurity broadening. Optical absorption peaks near 1, 2, and 3.4 eV are associated with direct interband transitions originating from the N1′, Γ25′, and P4 symmetry points, with a contribution to the 1-eV absorption from transitions from the Fermi surface to the flat unoccupied band extending through N4, Γ12, P3, and H25′.
The American Physical Society
Bos, Laurence W. and Lynch, David W., "Optical Properties of Antiferromagnetic Chromium and Dilute Cr-Mn and Cr-Re Alloys" (1970). Physics and Astronomy Publications. 23.