TY - JOUR
T1 - Persistent photoconductivity in high-temperature superconductors with nano-scale fragmented copper-oxide chains
AU - Brantner, P.
AU - Markowitsch, Wilhelm
AU - Stockinger, Christian
AU - Lang, Wolfgang
AU - Siraj, Khurram
AU - Pedarnig, Johannes D.
AU - Bäuerle, Dieter
N1 - DOI: 10.1016/j.jnoncrysol.2005.12.058
Coden: JNCSB
Affiliations: Universität Wien, Institut für Materialphysik, Boltzmanngasse 5, A-1090 Wien, Austria; Johannes-Kepler-Universität Linz, Institut für Angewandte Physik, A-4040 Linz, Austria
Adressen: Markowitsch, W.; Universität Wien; Institut für Materialphysik; Boltzmanngasse 5 A-1090 Wien, Austria; email: [email protected]
Import aus Scopus: 2-s2.0-33750437773
29.10.2007: Datenanforderung 1949 (Import Sachbearbeiter)
PY - 2006
Y1 - 2006
N2 - We present studies of the relaxation of persistent photoconductivity in 60-K YB2C3Ox. By using thin films grown on vicinal SrTiO3 substrates, measurements of the in-plane (a-b plane) conductivity and of the out-of-plane (c-axis) conductivity were performed. The photo-induced enhancements of both conductivities showed the well-known stretched-exponential relaxation. We observed a small anisotropy of the relaxation rates of the two conductivity components. The relaxation of the c-axis conductivity appeared somewhat delayed compared to the a-b plane conductivity. In a simple thermal relaxation picture this finding implies different energy barriers for the c-axis and a-b plane relaxations, which is not consistent with generally accepted models of persistent photoconductivity in YB2C3Ox. We interpret the observed anisotropy as a consequence of the structural modifications of the copper-oxide chains that are induced by light illumination. Structural changes such as the re-ordering of the oxygen ions are slow processes compared to electronic excitations. Hence, the c-axis conductivity, which is more influenced by (small) structural modifications of the chain layer, needs a longer time to return to the equilibrium state after the cessation of the illumination. Œ 2006 Elsevier B.V. All rights reserved.
AB - We present studies of the relaxation of persistent photoconductivity in 60-K YB2C3Ox. By using thin films grown on vicinal SrTiO3 substrates, measurements of the in-plane (a-b plane) conductivity and of the out-of-plane (c-axis) conductivity were performed. The photo-induced enhancements of both conductivities showed the well-known stretched-exponential relaxation. We observed a small anisotropy of the relaxation rates of the two conductivity components. The relaxation of the c-axis conductivity appeared somewhat delayed compared to the a-b plane conductivity. In a simple thermal relaxation picture this finding implies different energy barriers for the c-axis and a-b plane relaxations, which is not consistent with generally accepted models of persistent photoconductivity in YB2C3Ox. We interpret the observed anisotropy as a consequence of the structural modifications of the copper-oxide chains that are induced by light illumination. Structural changes such as the re-ordering of the oxygen ions are slow processes compared to electronic excitations. Hence, the c-axis conductivity, which is more influenced by (small) structural modifications of the chain layer, needs a longer time to return to the equilibrium state after the cessation of the illumination. Œ 2006 Elsevier B.V. All rights reserved.
U2 - 10.1016/j.jnoncrysol.2005.12.058
DO - 10.1016/j.jnoncrysol.2005.12.058
M3 - Article
SN - 0022-3093
VL - 352
SP - 4500
EP - 4504
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
IS - 42-49 SPEC
ER -