Charge transfer-originated large Faraday rotation in Rh4+-substituted magnetic garnets

A large Faraday rotation is reported for Rh4+-substituted magnetic garnets in the near-infrared wavelength region. The Faraday rotation at 0.9 mu m is about seven times larger than that in yttrium iron garnet by substituting Rh4+ ions of only 0.13 per formula unit at room temperature. From the electronic state calculations of a (Rh4+O62-)(8-) octahedral cluster performed by using an unrestricted self-consistent field-scattering wave-X alpha method, the origin of the Faraday rotation is attributable to the charge transfer transitions of an electron from O 2p to Rh 4d orbitals, or t(1u)(n)(2p)-->t(2g)*(4d) and t(2)(un)(2p)-->t(2g)*(4d) transitions. Based on this assignment, the Faraday rotation spectrum is calculated by taking into account the spin-orbit interaction and the molecular field from iron magnetizations in the magnetic garnet. (C) 1997 American Institute of Physics.