| 摘要 |
PURPOSE:To realize recording and reading-out at high S/N or S/C by constituting a Faraday rotating element by a Bi-contg. rare earth iron magnetic garnet. CONSTITUTION:The Bi-contg. rare earth iron magnetic garnet is formed by liquid phase epitaxy on a transparent substrate to constitute the Faraday rotating element. >=1 kinds of nonmagnetic elements such as Ga and Al are doped in substitution of Fe of the Bi-contg. iron magnetic garnet in particular, i.e., to the Fe site thereof. The substitution quality of these nonmagnetic elements is particularly selected at 0.7-1.2/f.u of Fe (f.u: formula unit). The generation of Fe<3+> is suppressed by substituting the Fe of the rare earth iron magnetic garnet with the nonmagnetic element, by which the light absorptivity in the 0.8mum wavelength band is decreased but the decrease of the Faraday rotating power by the addition of the nonmagnetic elements is made smaller than the decrease thereof by contribution to the decrease of light absorptivity and the loss of light in the forward direction as an optical isolator is eventually remarkably improved by selecting the adding amt. of the nonmagnetic element.
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