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Vortex pinning in electron‐doped cuprate superconductor La 2– x Ce x CuO 4
Author(s) -
Zuev Yuri,
Lemberger Thomas R.,
Skinta John A.,
Greibe Tine,
Naito Michio
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200301692
Subject(s) - condensed matter physics , cuprate , doping , superconductivity , superfluidity , materials science , vortex , lattice constant , molecular beam epitaxy , epitaxy , electron , physics , nanotechnology , diffraction , optics , layer (electronics) , quantum mechanics , thermodynamics
We have measured the vortex pinning strength in thin films of the electron‐doped cuprate La 2– x Ce x CuO 4 for various doping x from x = 0.075 ( T c = 25 K) to x = 0.15 ( T c = 12.5 K). The optimal doping for this compound is ≈0.11, at which T c = 29 K. Films were prepared by a molecular‐beam epitaxy method. A structural XRD investigation revealed no doping‐induced lattice strain. We use a two‐coil technique at frequencies from 10 to 100 kHz. The superfluid density n s (0) grows rapidly with x on the underdoped side and decreases slowly on the overdoped side. The Labusch parameter κ , i.e. the spring constant for a pinned vortex, shows large variations as the doping changes. It increases with x rapidly to a maximum at slight underdoping and then it decreases on the overdoped side more rapidly than n s (0). Even at optimal doping κ (0) is an order of magnitude lower than the highest values observed in YBCO.