Raman scattering, electronic, and ferroelectric properties of Nd modified Bi₄Ti₃O₁₂nanotube arrays

Abstract

Neodymium-modified bismuth titanate, Bi₄−᙮Nd᙮Ti₃O₁₂(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 Bi₂O₂layers weaken and broaden with increasing Nd content. The changes of Raman internal modes originated from the vibrations of atoms inside the TiO₆ 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.