434 Y3-XBixFe5O12 Magneto-Optical Indicator Films Prepared by Metal Organic Decomposition Method

Friday, November 6, 2009: 10:00 AM
Pancho Villa (Camino Real Hotel)
Takayuki Ishibashi , Department of Materials Science and Technology, Nagaoka University of Technology, Niigata, Japan
Terumasa Kosaka , Department of Materials Science and Technology, Nagaoka University of Technology, Niigata, Japan
Masayuki Naganuma , Department of Materials Science and Technology, Nagaoka University of Technology, Niigata, Japan

Recently, Bi-substituted yttrium iron garnet, Y3-xBixFe5O12, (Bi:YIG), has been used as an indicator that visualizes magnetic flux distribution utilizing magneto-optical (MO) effect. In order to improve the sensitivity and the spatial resolution in the MO imaging, higher Bi substitution and thinness less than 1m are required as an MO indicator. For the purpose, Bi:YIG films with high Bi substitution of x = 0 - 2.5 were obtained on Gd3Ga5O12 (111) substrates by metal-organic decomposition (MOD) method. Faraday rotation was found to be 1.55 x 105 degree/cm at wavelength of 524 nm for Bi:YIG film with x = 2.5. We found that Bi:YIG films prepared by MOD method are promising for MO indicator films, since they have in-plane magnetization and no large zigzag magnetic domains disturbing a measurement of MO signals from a sample. Figures 1 and 2 show an MO imaging of superconducting Nb pattern. Figure 1 shows how to visualize magnetic flux around the Nb pattern, and Figure 2 shows an MO images measured at 4K measured using Bi:YIG (x = 1.0) with a thickness of 800 nm. Magnetic distribution that magnetic flux is excluded from the Nb pattern by the Meissner effect is clearly observed. The sensitivity in this measurement was smaller than 2 G.

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Fig.1 Visualization of magnetic flux using Bi:YIG film.

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Fig.2 An MO image of Nb film with magnetic field of 10 Oe at 4 K.