Effect of paramagnetic manganese ions doping on frequency and high temperature dependence dielectric response of layered Na sub(1.9)Li sub(0.1)Ti sub(3)O sub(7) ceramics

The manganese doped layered ceramic samples (Na sub(1.9)Li sub(0.1))Ti sub(3)O sub(7) : XMn(0.01 less than or equal to X less than or equal to 0.1) have been prepared using high temperature solid state reaction. The room temperature electron paramagnetic resonance (EPR) investigations exhibit that a...

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Bibliographic Details
Published in:Bulletin of materials science 2010-12, Vol.33 (6), p.691-696
Main Authors: Pal, Dharmendra, Pandey, J L
Format: Article
Language:English
Subjects:
Ceramics
Charge
Dielectric loss
Doping
Interlayers
Manganese
Manganese ions
Temperature dependence
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Summary:The manganese doped layered ceramic samples (Na sub(1.9)Li sub(0.1))Ti sub(3)O sub(7) : XMn(0.01 less than or equal to X less than or equal to 0.1) have been prepared using high temperature solid state reaction. The room temperature electron paramagnetic resonance (EPR) investigations exhibit that at lower percentage of doping the substitution of manganese ions occur as Mn super(3+) at Ti super(4+) sites, whereas for higher percentage of doping Mn super(2+) ions occupy the two different interlayer sodium/lithium sites. In both cases, the charge compensation mechanism should operate to maintain the overall charge neutrality of the lattice. The manganese doped derivatives of layered Na sub(1.9)Li sub(0.1)Ti sub(3)O sub(7) (SLT) ceramics have been investigated through frequency dependence dielectric spectroscopy in this work. The results indicate that the dielectric losses in these ceramics are the collective contribution of electric conduction, dipole orientation and space charge polarization. Smeared peaks in temperature dependence of permittivity plots suggest diffuse nature of high temperature ferroelectric phase transition. The light manganese doping in SLT enhances the dielectric constant. However, manganese doping decreases dielectric loss due to inhibition of domain wall motion, enhances electron-hopping conduction, and impedes the interlayer ionic conduction as well. Manganese doping also gives rise to contraction of interlayer space.
ISSN:0250-4707
0973-7669
DOI:10.1007/s12034-011-0139-8