Correlation between reduced dielectric loss and charge migration kinetics in NdFeO3-modified Ba0.7Sr0.3TiO3 ceramics Show others and affiliations
2021 (English) In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 32, no 20, p. 24910-24929Article in journal (Refereed) Published
Abstract [en]
The present study demonstrates the reduction in the dielectric loss at room temperature from 0.149 to 0.027 in the composite of (NdFeO3)0.1−(Ba0.7Sr0.3TiO3)0.9 as compared to the undoped Ba0.7Sr0.3TiO3 and correlates with the charge compensation due to the ionic substitutions for both A site (NdBa) and B (FeTi) site generated excess electrons, localized hole states and robust oxygen vacancies (VO) along with different cationic oxidation states. The VO mediated F center charge transfer mechanism i.e., bound magnetic polaronic behaviour and defect complex generated between acceptors and ionized VO reduce electrical conductivity and loss factor. The presence of weak ferromagnetism in the M-H loop reconfirms the F center exchange mechanism in mixed phase symmetry. The activation energy calculated from impedance spectroscopy, electrical modulus and electrical conductivity analysis supports the presence of doubly ionized VO. Further, density functional theory based first principle calculation manifests that the impurity induced depopulation of valence band edge electrons into a single spin up channel which distorts TiO6 octahedra with fluctuating bond length and Ti 3deg orbital splitting observed in decomposed density of states for accommodating excess electrons. These trapped and accommodated electrons reduce the effective electron concentration which in turn decreases the electrical conductivity and loss factor.
Place, publisher, year, edition, pages Springer Nature , 2021. Vol. 32, no 20, p. 24910-24929
Keywords [en]
Activation analysis, Activation energy, Binary alloys, Bond length, Charge transfer, Color centers, Density functional theory, Dielectric devices, Dielectric losses, Electric conductivity, Electrons, Ionization, Cationic oxidation state, Charge transfer mechanisms, Effective electrons, Electrical conductivity, First principle calculations, Impedance spectroscopy, Ionic substitutions, Weak ferromagnetism, Strontium compounds
National Category
Condensed Matter Physics
Identifiers URN: urn:nbn:se:kth:diva-316107 DOI: 10.1007/s10854-021-06949-5 ISI: 000695536100008 Scopus ID: 2-s2.0-85114305026 OAI: oai:DiVA.org:kth-316107 DiVA, id: diva2:1686505
Note QC 20220810
2022-08-102022-08-102024-01-10 Bibliographically approved