Raman scattering, electronic, and ferroelectric properties of Nd modified Bi4Ti3O12 nanotube arrays
ABSTRACT Neodymium-modified bismuth titanate, Bi 4- x Nd x Ti 3 O 12 (BNdT), nanotube arrays were fabricated by sol-gel method utilizing experimentally prepared porous anodic aluminum oxide (AAO) templates with pore diameters of about 200 nm and 100 nm, respectively. The as-prepared nanotube arrays exhibit orthorhombic perovskite polycrystalline structure of BNdT, which have outer diameters of about 200 and 100 nm, corresponding to the pores diameters of the AAO templates employed, and with wall thicknesses of about 9.7 nm and 12 nm, respectively. The phonon vibration modes corresponding to the Bi atoms in the Bi 2 O 2 layers weaken and broaden with increasing Nd content. The changes of Raman internal modes originated from the vibrations of atoms inside the TiO 6 octahedral indicate the increase in octahedron tilting and structural distortion. The leakage current and polarization-electric field response curves of BNdT nanotube arrays were measured, and the hysteresis loop illustrates a good ferroelectric property of as-prepared BNdT nanotube array at room temperature. The dielectric constant and dissipation factor were measured in the frequency region from 1 kHz to 1 MHz indicating polarization relaxation phenomenon.
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ABSTRACT: We report the structural and optical properties variation of Bi4-xNdxTi3O12 by different Nd substitution content for the first time. Bi4-xNdxTi3O12 thin films were fabricated by sol-gel process. X-ray diffraction and Raman scattering analysis reveal degradation in crystallinity and increase in distortion upon Nd doping. Grain size is suppressed as the increase of Nd content. Optical transmittance decreases from 63% to 43% at the wavelength of 600 nm as the Nd content increases from 0 to 0.85. Band gap energy increases from 3.4 to 3.5 eV when Nd content increases. Refractive index and extinction coefficient variations are also investigated.Integrated Ferroelectrics - INTEGR FERROELECTRICS. 01/2012; 133(1):73-80.