Faraday rotation effects of Mn/sup 2+/-modified Tb/sub 2/O/sub 3/-B/sub 2/O/sub 3/ glass in pulsed magnetic field

We present the dynamical Faraday rotation of a terbium metaborate glass (25Tb/sub 2/O/sub 3/-75B/sub 2/O/sub 3/) modified with Mn/sup 2+/ ions using pulsed magnetic fields, which reached up to /spl sim/16 T. The superexchange couplings of Tb/sup 3+/-O/sup 2-/-Tb/sup 3+/ or Tb/sup 3+/-O/sup 2-/-Mn/sup 2+/ were magnetooptically observed at lower temperature. In particular, the enhancement of the Faraday rotation effect was obtained at 15 K with repetitional operation of the 16-T pulsed magnetic fields, resulting in the destruction of the dimer couplings. When the operated glasses were heated back to 300 K, only the Tb/sub 2/O/sub 3/-B/sub 2/O/sub 3/:Mn/sup 2+/ exhibited a significant change in the Faraday rotation.