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|Title: ||Fabrication and characterization of pulsed laser deposition of La₁₋ₓCaₓMnO₃based heterostructures|
|Authors: ||Leung, Yau-shing|
|Subjects: ||Thin films.|
Pulsed laser deposition.
Hong Kong Polytechnic University -- Dissertations
|Issue Date: ||1998 |
|Publisher: ||The Hong Kong Polytechnic University|
|Abstract: ||Excellent quality epitaxial giant magnetoresistive (GMR) perovskite-like manganates oxide of La₁-ₓCaₓMnO₃ (LCMO) thin films have been fabricated by the Pulsed Laser Deposition (PLD) method. The LCMO films have been successfully grown on single crystal (100)LaAlO₃ (LAO) substrates and (100)Silicon (Si) substrates through buffers layers of Titanium Nitride (TiN) and Strontium Titanium Oxide, SrTiO₃ (STO). It has been found that the structural quality of the LCMO films improves at higher deposition temperatures and with post deposition annealing. The conductivity and the semiconductor-metal transition temperature (Tc), on the other hand, depend on the crystallinity and the oxygen content of the LCMO films. For deposition on (100)LAO single crystal substrates, a low threshold temperature of 650 °C for growing epitaxial LCMO films is detected. A magnetoresistance ratio (MR) of -50% at 170K under a B-field of 1.2T is achieved. For LCMO films prepared directly on (100)Si substrates, multi-phase films with Tc less than 77K (liquid nitrogen temperature) are obtained. By introducing buffer layers of TiN and STO, epitaxial LCMO films have been successfully grown on Si substrates. A MR of -50% at 116K under a B-field of 1.2T has been realized in the LCMO/STO/TiN/Si heterostructure.|
|Degree: ||M.Phil., Dept. of Applied Physics, The Hong Kong Polytechnic University, 1998|
|Description: ||v, 119 leaves : ill. ; 31 cm.|
PolyU Library Call No.: [THS] LG51 .H577M AP 1998 Leung
|Rights: ||All rights reserved.|
|Appears in Collections:||AP Theses|
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