Tetragonal tungsten-bronze-type strontium barium niobate(SBN) material is an attractive materials for many applications such as ferroelectric

pyroelectric

electro-optic

and photorefractive devices.A number of techniques for fabricating SBN ferroelectric films have been developed in the past years.Among these techniques

the pulsed laser deposition(PLD) technique is ideally suited to the epitaxial growth of SBN.The epitaxial Sr

0.61

Ba

0.39

Nb

2

O

6

SBN61 thin films deposited on MgO(100) substrate have been prepared by pulsed laser deposition(PLD).The structural properties of the thin films were studied by X-ray diffraction.The θ~2θ scan pattern indicates single crystalline layers with the(001) orientation perpendicular to the substrate plane.The diffraction of SBN61(001)

MgO(002) and SBN61(002) are identified

and no trace of other diffraction is observed.The films are thus with single phase with

c

-axis perpendicular to the substrate.The lattice constant of

c

=0.3923 nm was calculated

which is in good agreement with

c

=0.3935 nm for bulk SBN61.Optical studies by spectroscopic ellipsometry(SE) measurements were carried out

and their optical constants were determined.It is found that the refractive index of the SBN61 films is almost the same as that of SBN61 single bulk crystal.The birenfrigence shift as a function of applied voltage of SBN61 thin films on MgO(001) were measured.The SBN61 samples showed a quadratic response and quadratic electro-optic coefficient

R

has been derived to be 0.21×10

-16

(m/V)

2

at 632.8 nm.