Far infrared reflectivity of Pr-doped YBa2Cu3O7 thin films
A. El Azrak1*, M. Zazoui1, J. Meziane1, R. Mountasser1,
M. Hamedoun2, I. Zorkani2, R. Lobo3, N. Bontemps3
1 Laboratoire de Physique de la Matière Condensée, Faculté des Sciences et Techniques Mohammédia
B.P. 146 mohammédia - Maroc
2Laboratoire de Physique du Solide, Faculté des Sciences Fès, B.P. 1976, Fès - Maroc
3Laboratoire de Physique du Solide, ESPCI, 10 rue Vauquelin 75005, Paris –France
* Corresponding author.
Received: 26 March 2006; revised version accepted: 22 June 2006
We report the room-temperature optical reflectivity on a set of Y1-xPrxBa2Cu3O7 thin films for x = 0 (Tc ˜ 90 K), x=0.3 (Tc˜50K), x = 0.4 (Tc ˜ 35 K) and x = 0.5 (Tc ˜ 19 K), in the 30-22000 cm-1 frequency range. The Pr concentration dependences of phonons features were studied. From the reflectivity, we obtain the real part of the frequency dependent optical conductivity s(w) by Kramers-Kronig transformation (TKK). We find that the plasma frequency decreases with the increase of Pr content (x). This variation is consistent with the higher dc resistivity. We discuss the implication of these results for the understanding of both transport phenomena and pairing mechanism in high-Tc superconductor thin films.
Keywords: Far infrared reflectivity; optical conductivity; Phonons; plasma frequency