Enhancement of Interfacial Polarization in BaTiO₃ Thin Films via Oxygen Inhomogeneity

Abstract

magnetic, and optical properties. [1,2] Particularly in ferroelectric materials, the substrate-induced epitaxial strain can lead to lattice deformation and enhance the ferroelectric properties, for instance, the enhanced ferroelectric transition temperature of BaTiO 3 (BTO) and room temperature ferroelectricty of SrTiO 3 (STO). [3] However, the strain engineering is basically hampered due to limited commercially single crystal substrates and film-thickness-driven strain relaxation. Another tuning strategy is defects control. The defects, including point defects and extended defects sometimes unavoidable even in well-controlled growth conditions. They are usually detrimental to ferroelectricity, such as the increase of leakage current induced by oxygen vacancies, as well as the decrease of local spontaneous polarization near the defects. [4,5] However, defects can also be used to enhance the ferroelectric properties in some well-controlled conditions. [6] It was reported that the distortion due to coupling between strain and point cation defect complexes (so-called defect dipole) alignment could be associated with enhancement of ferroelectric Curie temperature and some other properties change. [7,8] From the aspect of oxygen vacancies, Liu et al. found that the

Thickness-Dependent Polar Domain Evolution in Strained, Ultrathin PbTiO3 Films

“…28 So, the fundamental contribution of the LSMO layer is to screen the depolarization field, possibly making the c domain wider. 39,40 The influence of the electrode on the a/c domain is not as obvious as that on the 180°domain. The use of LSMO electrodes may cause flexible polarization rotation in PTO films.…”

“…The a / c domain walls in PTO films are indistinct even after epitaxial growth of the 30 nm-thick PTO film . So, the fundamental contribution of the LSMO layer is to screen the depolarization field, possibly making the c domain wider. , The influence of the electrode on the a / c domain is not as obvious as that on the 180° domain. The use of LSMO electrodes may cause flexible polarization rotation in PTO films. , The use of the electrode to screen the depolarizing field was confirmed to reduce the 180° domains .…”

Domain Switching in BaTiO3 Films Induced by an Ultralow Mechanical Force

“…Mechanical switching has been reported in a series of ferroelectric materials, such as BiFeO 3 , − BaTiO 3 , , (1 – x )­Pb­(Mg 1/3 Nb 2/3 )­O 3 - x PbTiO 3 ( x = 0.32, 0.40), Pb­(Zr 0.2 Ti 0.8 )­O 3 , PbZr 0.48 Ti 0.52 O 3 . The flexoelectric effect on ferroelectric polarization was investigated by regulating the lattice mismatch with the substrates, oxygen vacancy, ,, and deposition temperature during the film growth and bending the substrate directly . Many strategies have been conducted to decrease the threshold force of ferroelectric domain switching.…”