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Journal of the Magnetics Society of Japan
Vol. 32 (2008) No. 2_2 P 140-145



Contributed Paper

We survey the properties of all-garnet magneto-optical (MO) heteroepitaxial film structures grown by pulsed laser deposition and rf-magnetron sputtering. 1D MO-photonic crystals (MOPCs) were composed of λ/4 garnet layers alternating highly gyrotropic Bi3Fe5O12 (BIG) and MO-passive rare earth gallium garnets. As designed, MOPCs' spectra exhibit optical stop band with the transmittance central peak caused by light localization in λ/2 thick BIG cavity. The first all-garnet BIG/YIG MOPC showed 140% enhancement of the Faraday rotation (FR) compared to a single layer BIG film [APL 84, 1438 (2004)]. Further improvement of MO-performance has been achieved due to the replacement of optically dense YIG by transparent Gd- (GGG), Sm- and novel La-Ga-garnets [APL 86, 141108 (2005); 87, 122504 (2005); 90, 191113 (2007); JAP 101, 053906 (2007)]. At the resonance wavelengths 750 (980) nm, specific FR θF = −20.5 (−7.3) deg/μm and MO-quality factor Q=2 | θF | /absorption=66 (43.6) deg represent the highest MOPC performance achieved so far. Respectively, this is 470 (810) % and 31 (190) % enhancement compared to a single layer BIG. MO-remanence (latching capability) has been engineered in the series of BIG:GGG (n:m) superlattices. Regular alternating of lattice mismatched garnet layers impedes the nucleation of misfit dislocations, preserves a long range coherent compressive strain through the whole multilayer thickness thus results in a strong uniaxial magnetic anisotropy. 2.5 μm thick BIG:GGG (3:2) film at 678nm shows FR = ± 1.4deg, transmittance 82%, 92% squareness of magnetization loop, saturation and coercive fields as low as 56 and 25 Oe, respectively. Nanostructured garnets were used to build MO-visualizer and current driven MO-display [APL 88, 242504 (2006)].

Copyright © 2008 The Magnetics Society of Japan

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