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Oxide Heterostructure. Shuhua Liang UTK Physics Dept. Perovskite Stucture ABO3. LCMO (magnetic material) La 0.67 Ca 0.33 MnO 3. High Tc Superconductor Lattice. LSCO (High Tc Sc) (La1-xSrxCuO3 ). YBCO High Tc Sc. YBa 2 Cu 3 O 7-x CuO 2 Plane More layers Higher Tc Distance
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Oxide Heterostructure Shuhua Liang UTK Physics Dept.
High Tc Superconductor Lattice • LSCO (High Tc Sc) (La1-xSrxCuO3 )
YBCO High Tc Sc • YBa2Cu3O7-x • CuO2 Plane • More layers Higher Tc • Distance • Carriers in CuO2 Plane
LaTiO3 layers (bright) of varying thickness spaced by 5 layers of SrTiO3 Metallic Interfaces between Insulators
LaTiO3 La 3+ one more e Ti 3+ Mott insulator A=0.397nm SrTiO3 Sr 2+ Ti 4+ Band insulator A=0.391nm
the Ti3+ signal is considerably wider than that of the La “Ti3+”~extra electron The ‘tail’ of Ti3+ have a decay length of 1nm as an order of screening length! Charge leakage
Fraction of Ti3+ is a function of the number of LaTiO3 unit cells. Conductivity is a function of the thickness of LaTi3 and SrTi3 Metallic Structure
CMR • Colossal magnetoresistance
Ca 2+ cause electron free to move. Double-exchange mechanism
Sc: YBa2Cu3O7-x FM: La0.67Ca0.33MnO3 Ferromagnetic/Sc oxide interface