Dielectric relaxation behavior of acceptor (Mg)-doped BaTiO3

Dielectric relaxation behavior of acceptor (Mg)-doped BaTiO3 ceramics was investigated with the increase of Mg concentration up to 0.6 mol. % in the temperature rang of 120 ∼ 540 °C. In the high temperature range above 320 °C, the activation energies of dielectric relaxation (Eτ) showed nearly simil...

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Veröffentlicht in:Journal of applied physics 2011-04, Vol.109 (8)
Hauptverfasser: Yoon, Seok-Hyun, Kwon, Sang-Hoon, Hur, Kang-Heon
Format: Artikel
Sprache:eng
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Zusammenfassung:Dielectric relaxation behavior of acceptor (Mg)-doped BaTiO3 ceramics was investigated with the increase of Mg concentration up to 0.6 mol. % in the temperature rang of 120 ∼ 540 °C. In the high temperature range above 320 °C, the activation energies of dielectric relaxation (Eτ) showed nearly similar values of ∼ 1.2 eV irrespective of Mg concentration. However, in the low temperature range below 320 °C, they continuously decreased from ∼ 1.2 eV and then saturated to ∼ 0.4 eV with the increase of Mg concentration. The activation energies of electrical conduction (Eσ) of the bulk grain evaluated by impedance analysis also showed almost the same behavior. Such coincidence demonstrates that the observed dielectric behaviors are caused by the space charge polarization at grain boundaries by conducting charge carriers. The disappearance of the dielectric relaxation in submicrometer fine-grain specimen also supports this mechanism. The variation of Eτ and Eσ with the increase of Mg concentration in the low temperature range was supposed to be caused by the dominant hopping conduction between ionized acceptor (MgTi″) and neutral or hole-trapped acceptor (MgTi×).
ISSN:0021-8979
1089-7550
DOI:10.1063/1.3582146