Numéro |
J. Phys. IV France
Volume 114, April 2004
|
|
---|---|---|
Page(s) | 401 - 402 | |
DOI | https://doi.org/10.1051/jp4:2004114097 |
J. Phys. IV France 114 (2004) 401
DOI: 10.1051/jp4:2004114097
Cooling rate dependence of the in-plane magnetic penetration depth
in
-type BEDT-TTF superconductors
N. Yoneyama1, 1, A. Higashihara1, T. Sasaki1, T. Nojima2 and N. Kobayashi2
1 Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
2 Center for Low Temperature Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
Abstract
We performed dc magnetization measurements under the
control of cooling-rate in the organic superconductors
-(BEDT-TTF)
2X
(
X=Cu(NCS)
2 and Cu[ N(CN)
2] Br). A distinct different cooling-rate
dependence of the in-plane magnetic penetration depth (
//(0)) was
observed between two salts, where
//(0) was estimated from a linear
extrapolation to 0 K. In the Cu(NCS)
2 salt,
//(0) remains
unchanged regardless of cooling-rate, while
Tc decreases slightly in
faster-cooling. On the other hand,
//(0) in the Cu[ N(CN)
2] Br salt
becomes long significantly in faster-cooling. We quantitatively explain the
change of
//(0) in the cooling-rate as an impurity effect by terminal
ethylene disorder in BEDT-TTF molecules in terms of the local and clean
limit approximation.
Key words. Organic superconductor, magnetization, penetration
depth, London model.
© EDP Sciences 2004