Dielectric and Ferroelectric Properties of Sr_xBa_1-xNb₂O₆(SBN:x) Thin Films

Abstract

Thin films of Sr x Ba 1−x Nb 2 O 6 (SBN:x) are particularly attractive for their potential use as low voltage electro-optic waveguides. This potential application in integrated optics requires the control of the (001) oriented SBN growth on a conductive substrate. We have prepared (001) SBN:x thin films on Pt coated MgO substrates by using sputtering techniques and rapid thermal annealing. The dielectric non linearity of the SBN:x films is investigated as a function of the Sr content (x = 50, 60, or 70%) and annealing conditions. It is maximum at the ferroelectric-paraelectric transition temperature of the film (175 • C, 116 • C and 40 • C for x = 50, 60, and 70% respectively). At room temperature and with a Sr content of 60%, the relative variation of the dielectric permittivity [ε(0)-ε(E)]/ε(0) is found equal to 46% for an applied electric field E = 43 kV/cm. Due to a transition temperature closer to room temperature, a dielectric non linearity of higher value, less sensitive to temperature and little affected by hysteresis, is expected from films of higher Sr content.

Simultaneous characterization of the electro-optic, converse-piezoelectric, and electroabsorptive effects in epitaxial (Sr,Ba)Nb2O6 thin films

“…Parameters of Pt and SBN deposition have been fixed from the results of previous investigations in which we established conditions for a stoichiometric composition of the amorphous SBN deposit 33 and for an epitaxial crystallization of a single phase SBN on Pt covered MgO substrates. 34,35 Amorphous SBN films are crystallized in a rapid thermal annealing furnace at 1160°C during a few seconds. The ͑001͒ oriented growth of SBN on Pt occurs exclusively on ͑001͒ oriented Pt.…”

“…When films are prepared in the optimized deposition and crystallization conditions, they exhibit ferroelectric properties and a strong dielectric non linearity at room temperature. 35 A relative variation in dielectric permittivity ͓ 3 ͑E͒ − 3 ͑0͔͒ / 3 ͑0͒ of 46% may be obtained by applying an electric-field E of about 4 V / m. Some typical properties of the SBN films we have developed are summarized in Fig. 5.…”

Experimental setup for high-temperature in situ studies of crystallization of thin films with atmosphere control

“…Polycrystalline growth -fast heating rate An SBN thin film, which has a large range of application possibilities (Lukasiewicz et al, 2008), was annealed with the highest heating rate (20 C s À1 ) possible for the setup. Physical vapor deposition and CSD of SBN on MgO or STO substrates have been reported because of the small lattice mismatch that could favor epitaxial growth (Infortuna et al, 2006;Boulay et al, 2007;Lam et al, 2018;Shirokov et al, 2018). Here, a singlecrystalline STO (100)-oriented substrate was used with a single deposited layer of SBN with Sr:Ba = 40:60.…”

Strontium Barium Niobate Thin Films for Dielectric and Electro-Optic Applications

“…The dielectric loss current is also integrated and may significantly contribute to form the observed hysteresis loop. (Glass, 1969) and for epitaxial SBN films (Boulay, 2007). (Boulay et al, 2007).…”

“…(Glass, 1969) and for epitaxial SBN films (Boulay, 2007). (Boulay et al, 2007). Top platinum dots (0.5 and 0.3 mm in diameter) have been deposited by using R.F.…”