Spectral Origins of Giant Faraday Rotation and Ellipticity in Bi- Substituted Magnetic Garnets
Abstract
Electrical permittivity theory has been applied to the interpretation of data describing the anomalously high Faraday rotation and ellipticity in the Y(3-x)Bi(x)Fe5O12 ferrimagnetic system. By the use of exact forms of the basic phenomenological equations for the off-diagonal tensor element epsilon (1sub)= epsilon'(1sub)+ epsilon (1sub), the measured Bi(3+) influence on the separate component epsilon'1 and epsilon (1sub) spectra from 1 to 5 eV has been closely fitted to theory by the superposition of three Fe(3+) (diamagnetic) electric dipole transitions occurring at 2.6, 3.15, and 3.9 eV, respectively. The strong transition at 3.15 eV that is believed to originate from Fe-06 molecular complexes of the octahedral sublattice may also have a smaller companion peak in the vicinity of 5 eV. Transition bandwidths and excited-state splittings determined from the matching of theory to experiment both indicate that strong Bi covalent interactions exist with the Fe-06 and Fe-04 complexes. These results also confirm that the enhanced magneto-optical effects in the longer-wavelength region (Lambda approx. 1 micrometer) are dominated by the tail of the epsilon'(1sub) diamagnetic peak at 3.15 eV.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 15, 1993
- Accession Number
- ADA268368
Entities
People
- Gary A. Allen
- Gerald F. Dionne
Organizations
- Massachusetts Institute of Technology