https://doi.org/10.1007/s100510050511
Low temperature penetration depth and the effect of quasi-particle scattering measured by millimeter wave transmission in YBa2Cu3O7-δ thin films
1
Laboratoire de
Physique de la Matière Condensée, École Normale Supérieure, 24 rue
Lhomond, 75231 Paris Cedex 05, France
2
Brockhouse Institute for Materials Research, McMaster University, Hamilton
On. L8S 4M1, Canada
3
Laboratoire de Chimie du Solide et Inorganique
Moléculaire, Université de Rennes I, avenue du Général Leclerc, 35042
Rennes Cedex, France
Corresponding author: a Louis-Anne.deVaulchier@physique.ens.fr
Received:
22
January
1998
Revised:
18
May
1998
Accepted:
9
June
1998
Published online: 15 October 1998
Measurement of the penetration depth 
as a function of
temperature using millimeter wave transmission in the range 130-500 GHz
are reported for three 
(YBCO) laser ablated thin
films. Two films, deposited on a 
substrate (
), exhibit a narrow resistive transition (
). One has been
subsequently irradiated with 
ions in order to increase the
scattering rate of the quasi-particles (
). The third
film, grown on MgO (
), exhibits also a fairly narrow
transition (
) and a high crystalline quality. The experiment
provides the absolute value 
for the penetration
depth at low temperature: the derivation from the transmission data and the
experimental uncertainty are discussed. We find a zero temperature
penetration depth 
Å, 
Å and 
Å, for YBCO-500 Å/
(pristine), YBCO-1300 Å /MgO and YBCO-500 Å / (irradiated)
respectively. exhibits a different behavior for
the three films. In the pristine sample, shows a
clear temperature and frequency dependence, namely the temperature
dependence is consistent with a linear variation, whose slope decreases with
frequency: this is considered as an evidence for the scattering rate being
of the order of the measuring frequency. A two fluids analysis yields
.
In the two other samples, does not display any
frequency dependence, suggesting a significantly larger scattering rate. The
temperature dependence is different in these latter samples. It is consistent
with a linear variation for the YBCO/MgO sample, not for the YBCO/
irradiated one, which exhibits a T2 dependence up to 
. We have
compared our data to the predictions of the d-wave model incorporating
resonant scattering and we do not find a satisfactory agreement. However, the
large value of 
in the pristine sample is a puzzle and sheds
some doubt on a straightforward comparison with the theory of data from thin
films, if considered as dirty d-wave superconductors.
PACS: 07.57.c – Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques / 74.72.h – High-Tc compounds / 74.76.w – Superconducting films
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998
