Garnet superlattice as a transparent above-room-temperature polar magnet.

The interface magnetic state in the garnet superlattices has been investigated by measuring the magnetization-induced second harmonic generation. Among the superlattice films being composed of sequentially stacked two or three different compositions of garnet layers including a magnetic yttrium iron garnet, while the centrosymmetric bicolor superlattices show little magnetic field effect, the tricolor superlattice exhibits a large nonlinear Kerr rotation manifesting a polar magnetic state formed at the interface. Furthermore, we found that the interface magnetic state is switchable by a tiny magnetic field (∼5 mT) over a wide temperature range up to about 550 K, and the material itself is visibly transparent, which will promise a potential magnetoelectric optical element. [ABSTRACT FROM AUTHOR]