Document Type

Article

Publication Date

12-1970

Journal or Book Title

Physical Review B

Volume

2

Issue

11

First Page

4567

Last Page

4577

DOI

10.1103/PhysRevB.2.4567

Abstract

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′.

Comments

This article is from Physical Review B 2 (1970): 4567, doi:10.1103/PhysRevB.2.4567. Posted with permission.

Copyright Owner

The American Physical Society

Language

en

File Format

application/pdf

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