AN INVESTIGATION OF THE LOW-TEMPERATURE FARADAY-ROTATION SPECTRUM OF BAFE12O19

The Faraday rotation spectra between 1.5 eV and 2.4 eV are examined fo r thin films of the hexagonal ferrite BaFe12O19, prepared by pulsed la ser deposition. Fine spectral detail is observed at 24 K between 1.69 eV and 1.85 eV. A sharp paramagnetic transition at 1.69 eV, with an os cillator strength of 5 x 10(-2), is assigned to the (6)A(1g)(S-6) --> T-4(2g)((4)G) crystal field transition originating on the 4f(2) octahe drally coordinated Fe3+ site. Somewhat weaker diamagnetic transitions above 1.73 eV are tentatively assigned to first-excited-state transiti ons in the 2b trigonal bipyramidal Fe3+ site. A broader feature with a n extremum at 2.23 eV is considered to originate from the (6)A(1)(6S) --> T-4(2)((4)G) transition in 4f(1) tetrahedral sites.