DocumentCode :
2779945
Title :
Phase relation, dielectric and ferroelectric properties of lead-free ferroelectric (1-x)Na0.5Bi0.5TiO3-xBaTiO3 thin films obtained by PLD and RF-PLD
Author :
Scarisoreanu, N.D. ; Craciun, F. ; Birjega, R. ; Dinescu, M.
Author_Institution :
NILPRP Bucharest, Bucharest, Romania
fYear :
2009
fDate :
14-19 June 2009
Firstpage :
1
Lastpage :
1
Abstract :
Sodium bismuth titanate (Na1/2 Bi1/2) TiO3, pure or in solid solution with BaTiO3, (1-x)Na0.5Bi0.5TiO3-xBaTiO3, can be a promising lead-free ferroelectric material for replacing lead zirconate titanate. In bulk, at morphotropic phase boundary (x = 0.06) it has attractive properties such as remanent polarization of 38 muC cm-2 and a coercive field of 73 kV cm-1 at room temperature, with a relatively high Curie temperature (320degC). In this work, the morphological, structural and electrical properties of NBT-BT thin films (with x values from 0 to 0.08) prepared by pulsed laser deposition (PLD) and radiofrequency assisted pulsed laser deposition (RF-PLD) were investigated. A parametric study concerning the influence of substrate temperature, RF power, x value and the reactive gas pressure was carried out. The deposited layers were characterized by XRD, SEM, AFM, TEM and SE (Spectroscopic Ellipsometry). Dielectric and ferroelectric properties were investigated up to 110 MHz using an impedance analyzer and a RT 66A Ferroelectric Test System. We report structural, dielectric and ferroelectric properties of sodium bismuth titanate - barium titanate (NBT-BT), thin films grown on Pt(111)/Si and MgO (100) by pulsed laser deposition (PLD) and radiofrequency beam discharge assisted PLD (RF-PLD). Structural investigations show that XRD spectra of PLD-grown films correspond to single-phase pseudoperovskite and indicate coexistence of rhombohedral and tetragonal phases (morphotropic phase boundary, MPB), as for the target. These films are polycrystalline and randomly oriented. The spectra of RF-PLD grown films correspond to (001)-oriented single-phase pseudoperovskite with rhombohedral distortion, as if the MPB would be displaced towards a slightly higher barium titanate content. Since the other deposition parameters have been the same, it seems that RF-PLD growth induces a higher s- tress in the deposited films than normal PLD and favours the rhombohedral structure.
Keywords :
Curie temperature; X-ray diffraction; atomic force microscopy; barium compounds; bismuth compounds; ellipsometry; ferroelectric coercive field; ferroelectric thin films; pulsed laser deposition; scanning electron microscopy; sodium compounds; transmission electron microscopy; Curie temperature; Na0.5Bi0.5TiO3-BaTiO3; X-ray diffraction; atomic force microscopy; coercive field; dielectric properties; ferroelectric thin films; morphotropic phase boundary; phase relation; pulsed laser deposition; radiofrequency beam discharge assisted PLD; remanent polarization; scanning electron microscopy; sodium bismuth titanate; spectroscopic ellipsometry; transmission electron microscopy; Bismuth; Dielectric thin films; Environmentally friendly manufacturing techniques; Ferroelectric materials; Optical pulses; Pulsed laser deposition; Radio frequency; Sputtering; Temperature; Titanium compounds;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Lasers and Electro-Optics 2009 and the European Quantum Electronics Conference. CLEO Europe - EQEC 2009. European Conference on
Conference_Location :
Munich
Print_ISBN :
978-1-4244-4079-5
Electronic_ISBN :
978-1-4244-4080-1
Type :
conf
DOI :
10.1109/CLEOE-EQEC.2009.5191774
Filename :
5191774
Link To Document :
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