Abstract:
The Faraday and the polar magnetooptical Kerr effects in undoped Bi12SiO20 (BSO) crystals have
been investigated. The dependence of a turn angle of polarization plane on magnetic induction for both
effects was established to be nonlinear. The results were interpreted within the framework of combined
electromagnetogyration model. Electrogyration part of the contribution was due to the formation of
the longitudinal internal electric field induced by optical spin orientation. It was shown that magnetism
of nonshared electronic pairs of Bi-O hepthaedra made the contribution in the total gyration of BSO
crystal.