All-garnet magneto-optical photonic crystals
2008 (English)In: Journal of the Magnetics Society of Japan, Vol. 32, no 2, 140-145 p.Article in journal (Refereed) Published
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 /4 garnet layers alternating highly gyrotropic B13Fe5O12 (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 /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 F=-20.5 (-7.3) deg/m and MO-quality factor Q = 2 |F| /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 m thick BIG:GGG(3:2) film at 678 nm shows FR=1.4 deg, 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)].
Place, publisher, year, edition, pages
Japan, 2008. Vol. 32, no 2, 140-145 p.
bismuth compounds, coercive force, compressive strength, dislocations, Faraday effect, gadolinium compounds, light transmission, magnetic anisotropy, magnetic epitaxial layers, nucleation, photonic crystals, pulsed laser deposition, sputter deposition, transparency
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:kth:diva-59898OAI: oai:DiVA.org:kth-59898DiVA: diva2:476624
FunderSwedish Research Council
Bi3Fe5O12-Gd3Ga5O12. QC 201201202012-01-122012-01-122012-01-20Bibliographically approved