Far infrared transmission spectra of Bi2Sr2Ca1(Cu1-x,Znx)2O8+δ, 0.0≤x≤0.05, crystallites in the normal state: Detection of superconducting gap precursors

MASSA, N.E.; RASINES, I.; NIEVA, G.; CAMPÁ, J.A.; FAINSTEIN, C.

PHYSICA C - SUPERCONDUTIVITY

ELSEVIER SCIENCE BV

Año: 1994 vol. 236 p. 1065 - 1066

0921-4534

We report transmission spectra of crystallites, taken from single crystal specimens of two plane Bi2Sr2Ca1(Cu1-x,Znx)2O8+δ, 0.0≤x≤0.05, diluted in CsI or polyethylene matrices In addition to weaker features assigned to unscreened phonons and a continuous background probably due to carriers, we found that the ratios of room temperature spectra to those taken lowering the temperature in 50 degrees intervals signal the presence of superconducting gap behavior with 2Δ kBTc∼6. We verified this by down shifting frequency as a function of Zn increment and the lowering of Tc induced by this strong superconductivity suppressor. Our preliminary search for phonons self-energy effects close to the superconducting transition temperature gave negative results. © 1994.