&lt;title&gt;Far-infrared reflectivity of Bi&lt;formula&gt;&lt;inf&gt;&lt;roman&gt;2&lt;/roman&gt;&lt;/inf&gt;&lt;/formula&gt;Sr&lt;formula&gt;&lt;inf&gt;&lt;roman&gt;2&lt;/roman&gt;&lt;/inf&gt;&lt;/formula&gt;CaCu&lt;formula&gt;&lt;inf&gt;&lt;roman&gt;2&lt;/roman&gt;&lt;/inf&gt;&lt;/formula&gt;O&lt;formula&gt;&lt;inf&gt;&lt;roman&gt;8+delta&lt;/roman&gt;&lt;/inf&gt;&lt;/formula&gt; single crystals with different oxygen contents&lt;/title&gt;

Martin Prenninger,Anton Prueckl,Donald M Pooke,Harry S Barowski,Karl F Renk,Matthias Stumpf,Kohji Kishio,Evgeny V Pechen,Philipp Keller,Robert G Buckley

doi:10.1117/12.241796

Abstract

Results are reported of an infrared reflectivity study of two high Tc superconducting Bi2Sr2CaCu2O8 plus delta single crystals. One of the samples was optimally- doped (Tc equals 91 K) and the other over-doped (Tc equals 73 K). It is observed that the reflectivity of the optimally-doped crystal is near unity at low temperature (10 K) and at frequencies below 400 cm-1. The reflectivity of the over-doped crystal is significantly less than unity. The dynamical conductivity and the penetration depth of the optimally-doped crystal are similar to values for optimally-doped YBa2Cu3O7- delta single crystal. However, the over-doped crystal displays significantly larger low frequency absorption. The results can be understood within a d-wave picture in which pair breaking increases with increasing hole doping and contributes to a significant quasiparticle density below Tc.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

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