Orientation Dependence of Ferroelectric Properties of Pulsed-Laser-Ablated Bi4-xNdxTi3O12 Films

TL;DR

This study investigates how the orientation of pulsed-laser-ablated Nd-doped Bi4Ti3O12 films affects their ferroelectric properties, revealing strong orientation dependence with significant variations in polarization and coercive fields.

Contribution

It demonstrates the orientation-dependent ferroelectric behavior of Nd-doped Bi4Ti3O12 films grown by pulsed-laser deposition, highlighting the relationship between crystal orientation and ferroelectric activity.

Findings

No ferroelectric activity in (001)-oriented films

Significant polarization in (118)- and (104)-oriented films

Crystallographic orientation influences ferroelectric properties

Abstract

Epitaxial (001)-, (118)-, and (104)-oriented Nd-doped Bi4Ti3O12 films have been grown by pulsed-laser deposition from a Bi4-xNdxTi3O12 (x=0.85) target on SrRuO3 coated single-crystal (100)-, (110)-, and (111)-oriented SrTiO3 substrates, respectively. X-ray diffraction illustrated a unique epitaxial relationship between film and substrate for all orientations. We observed a strong dependence of ferroelectric properties on the film orientation, with no ferroelectric activity in an (001)-oriented film; a remanent polarization, 2Pr, of 12 microC/cm2 and coercive field, Ec, of 120 kV/cm in a (118)-oriented film; and 2Pr = 40 microC/cm2, Ec = 50 kV/cm in a (104)-oriented film. The lack of ferroelectric activity along the c-axis is consistent with the orthorhombic nature of the crystal structure of the bulk material, as determined by powder neutron diffraction.