BI-DYIG FILMS - ENHANCEMENT OF THE DY CONTRIBUTION TO THE FARADAY-ROTATION

The Faraday rotation of epitaxial garnet films of composition {R(3-x)B i(x)}[Fe-2](Fe-3)O-12 with R=Dy, Y, and high Bi content (x congruent t o 1.30) has been measured in the temperature range 10 K < T < 600 K at lambda = 1155 nm. The analysis of the data in terms of the sublattice magnetization reveals a strong contribution of the {Dy} sublattice. T he ''electric'' dipole Faraday rotation per Dy ion has been determined and compared to its value in the bismuth-free dysprosium garnet. It t urns out that Bi gives rise to a pronounced enhancement of this contri bution. This result is compared with that observed for other Bi-substi tuted tare-earth iron garnets in the visible band. (C) 1996 American I nstitute of Physics.