FARADAY-ROTATION OF BISMUTH SUBSTITUTED DYSPROSIUM IRON GARNETS

The Faraday rotation on single crystal garnets of composition Dy-3-x Bi-x Fe5O12 with x = 0.43 has been investigated in the temperature range 10 K < T < 300 K at lambda = 1150 nm. The data are described in terms of the corresponding sublattice magnetizations assuming that the contribution of the Fe3+ ions to Faraday rotation (FR) is the same as for bismuth substituted yttrium garnet (for identical x value). The 1st order magneto-optical (MO) coefficient (C-e of the Dy3+ ion is deduced; in the spontaneous state, C-e is linear temperature dependent as previously found in ''pure'' DyIG with a decrease of C-e of about 30 - 50 % induced by the presence of bismuth.