Contrast enhancement of rare-earth switchable mirrors through microscopic shutter effect

D.G. Nagengast, A.T.M. van Gogh, Ernst S. Kooij, B. Dam, R. Griessen

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In contrast to the binary switchable mirror films (YHx, LaHx, REHx with RE:rare earth) which have a weak red transparency window in their metallic dihydride phase, rare-earth alloys containing magnesium are remarkable for the large contrast between their metallic dihydride and transparent trihydride phase. By means of structural, optical transmittance, and electrical resistivity measurements on a series of Y1−yMgyHx, films we show that this is due to a disproportionation of the alloy. While the yttrium dihydride phase is formed, Mg separates out, remaining in its metallic state. Upon further loading, insulating MgH2 is formed together with cubic YH3−δ. In this way Mg acts essentially as a microscopic optical shutter, enhancing the reflectivity of these switchable mirrors in the metallic state and increasing the optical gap in the transparent state.
Original languageUndefined
Pages (from-to)2050
Number of pages3
JournalApplied physics letters
Issue number14
Publication statusPublished - 1999


  • IR-75181

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