Low field driven latching-type Bi3Fe5O12∕Gd3Ga5O12 magneto-optical display

Series of heteroepitaxial all-garnet magneto-optical (MO) Bi3Fe5O12n∕Gd3Ga5O12m (BIGn∕GGGm, n=1, 2, 3, 4, 5 and m=1 and 2 are the numbers of unit cells) nanostructured multilayers have been sintered by pulsed laser deposition technique. Processing parameters and structure of grown films have been optimized to obtain perpendicular magnetic anisotropy and square hysteresis loop with low coercive and saturation magnetic fields. Regular alternating of lattice mismatched BIG and GGG atomic layers inhibited nucleation of misfit dislocations; thus a long range coherent compressive strain was preserved through the whole thickness of BIGn∕GGGm multilayer stack. 2.5μm thick BIG3∕GGG2 sample (1200 BIG and 800 GGG unit cells) at λ=678nm shows MO Faraday rotation ΘF=±1.4°, transmittance of 82%, attenuation α=3400dB∕cm, squareness of magnetization loop (remnant-to-saturation magnetizations ratio) as high as 92%, and saturation and coercive fields as low as 56 and 25Oe, respectively. MO remanence (latching capability) enables application of nanostructured garnet as a magnetic relief replicator/visualizer and as a material for low power consuming displays.