Influence of copper doping on structural and dielectric response on sodium lithium tri titanates (Na1.9Li0.1)Ti3O7:X Cu (0.0 ≤ X ≤ 0.1)

Abstract

Pure and Cu-doped [(Na1.9Li0.1) Ti3O7XCu (0.01 ≤ X ≤ 1.0)] layered ceramics are prepared via the conventional solid state reaction method. The microstructure, dielectric properties and ac conductivity of copper doped (Na1.9Li0.1) Ti3O7 have been investigated. The XRD results indicate that copper ions enter the unit cell maintaining the layered structure of solid solution. The dependence of loss tangent (tanδ) and relative permittivity (er) on temperature range (373–573 K) and frequency ranges (100 kHz–1 MHz) have been repeated for [(Na1.9Li0.1) Ti3O7]XCu (0.01 ≤ X ≤ 1.0)]. The dielectric losses in copper doped derivatives of layered (Na2-xLixTi3O7) (where X = 0.1) ceramic are the cooperative contribution of electrical conductions, dipole orientation and space change polarization. The peaks of relative permittivity at high temperature indicate a possible ferroelectric phase transition. It is observed that low doping of paramagnetic ions (Cu2+) enhances electron hopping (polaron) conduction and impedes the interlayer ionic conduction. However, electron hopping conduction is dominant over lower temperature region, but as temperature raises interlayer ionic conduction begins to prevail.