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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 23:12 |
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Conference: Bucharest University Faculty of Physics 2015 Meeting
Section: Solid State Physics and Materials Science
Title:
the study of electric/ferroelectric properties in heterostructures with ferroelectric and/or multiferroic properties
Authors:
A.G. BONI(1,2), C. CHIRILA(2),L.M. HRIB(2), I. PASUK(2), L. TRUPINA(2), S. GRECULEASA(1,2), V. KUNCSER(2) ,R. NEGREA(1,2), I. PINTILIE(2), L. PINTILIE(2)
Affiliation:
1) University of Bucharest, Faculty of Physics, Magurele 077125, Romania
2) National Institute of Materials Physics, Atomistilor 105bis, Magurele, Ilfov, 77125, Romania
E-mail
andra.boni@infim.ro
Keywords:
Multiferroic, multilayers, pulse laser deposition, ferroelectric, electrode interface, potential barrier, leakage current, hysteresis, capacitance
Abstract:
Capacitor-like structures based on thin films heterostructures are prepared by pulsed laser deposition. As ferroelectric materials Pb(Zr,Ti)O3 and BaTiO3 have been used. The influence of the substrate and of the top electrode on polarization reversal, capacitance, and leakage current are evaluated. It is shown that the metal-ferroelectric-metal structures can be modeled as two Schottky diode connected back-to-back, and the leakage current follow the Schottky-Simmons equation. Also it is found that potential barrier formed at the interface of ferroelectric-electrode is dependent on polarization bound charges and it is almost independent on the choice of top electrode. Also oxide heterostructures with ferroelectric and ferromagnetic properties known as “artificial multiferroic” have been studied. As ferroelectric material a PZT layer have been deposited and as magnetic materials a CoFeO3 and/or La(Sr,Mn)O3 have been used. It is found that the association between the hard magnetic spinel CFO and the ferromagnetic half-metallic oxide LSMO enhance the ferromagnetic properties. All structures present very good ferroelectric properties, with rectangular hysteresis loops and butterfly-shape of current-voltage characteristics. The leakage current and the polarization mechanisms (studied by impedance spectroscopy) are analyzed as a function of symmetry of the structure, the thickness of ferroelectric layer and the bottom electrode choice.
Acknowledgement:
A.G. Boni and S. Greculeasa ,thanks the strategic Grant POSDRU/159/1.5/S/137750, ‘‘Project Doctoral and Postdo Andra Georgia Boni thanks the strategic Grant POSDRU/159/1.5/S/137750, ‘‘Project Doctoral and Postdoctoral programs support for increased competitiveness in Exact Sciences research’’ co-financed by the European Social Found within the Sectorial Operational Program Human Resources Development 2007–2013.ctoral programs support for increased competitiveness in Exact Sciences research’’ co-financed by the European Social Found within the Sectorial Operational Program Human Resources Development 2007–2013.
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