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Title: | THE ROLE OF ATOMIC INTERFACES ON ELECTRONIC, MAGNETIC AND SWITCHING PROPERTIES OF OXIDE HETEROSTRUCTURES | Authors: | LI CHANGJIAN | Keywords: | Oxides Heterostructures, Pulsed Laser Deposition, Magnetism, Polar Discontinuity, Two Dimensional Electron Gas, Ferroelectric Tunnel Junction | Issue Date: | 31-Jul-2015 | Citation: | LI CHANGJIAN (2015-07-31). THE ROLE OF ATOMIC INTERFACES ON ELECTRONIC, MAGNETIC AND SWITCHING PROPERTIES OF OXIDE HETEROSTRUCTURES. ScholarBank@NUS Repository. | Abstract: | Functional oxides with wide spectra of properties hold promising applications in future multifunctional devices. In this thesis, three materials systems, LaAlO3/SrTiO3, LaMnO3/SrTiO3 and ferroelectric tunnel junction (FTJ) of Pt/(La0.67Sr0.33MnO3/La1-xSrxMnO3/)BaTiO3//Nb:SrTiO3 are studied for electronic, magnetic and switching properties, respectively. In LaAlO3/SrTiO3, we firstly clarified the origin of conductive interface between to band insulator, then revealed relative dominance of electron scattering mechanisms near the metal-insulator-transition regime and finally we determined a critical crystallinity (70 % at temperature 515 ?C) for two dimensional electron gas at the interface. In LaMnO3/SrTiO3 interfaces, we conclusively demonstrated 6 unit cell (uc) of the critical thickness for the transition both in bulk and microscopic measurements with support of a theoretical model of the electronic reconstruction. In the ferroelectric tunnel junction study, we showed that additional interfaces increase tunnel electroresistance (TER) of an FTJ at the expense of the resistance area product (RONA) originated from the band offset effects at the interfaces within an FTJ. We are the first to show TER of 400% at room temperature for FTJ of Pt/BaTiO3/Nb:SrTiO3 with the BaTiO3 only of 0.8 nm (2 uc). In summary, electrostatic boundary conditions and band offsets at oxide interfaces are extremely important parameters to be considered and utilized to build multifunctional devices. | URI: | http://scholarbank.nus.edu.sg/handle/10635/121996 |
Appears in Collections: | Ph.D Theses (Open) |
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