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Colossal Dielectric Behavior and Dielectric Relaxation of (Li, Fe) Co‐Doped ZnO Ceramics
Author(s) -
Wu You,
Li Jun,
Bai Han,
He San,
Hong Yang,
Shi Kouzhong,
Zhou Zhongxiang
Publication year - 2018
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201800126
Subject(s) - dielectric , materials science , doping , ceramic , dielectric loss , relaxation (psychology) , permittivity , analytical chemistry (journal) , dielectric permittivity , grain boundary , condensed matter physics , microstructure , composite material , optoelectronics , chemistry , physics , psychology , social psychology , chromatography
The co‐doped ceramics (Fe 0.5 Li 0.5 ) x Zn 1− x O ( x = 0.005, 0.01, 0.015) (abbreviated as FL‐0.005, FL‐0.01, and FL‐0.015) as well as the Fe‐only and Li‐only (abbreviated as Fe‐0.01 and Li‐0.01) doped samples are prepared by a solid‐state reaction method to investigate their colossal dielectric property for the first time. The permittivity value ( ɛ ′ ≈ 2.05 × 10 4 at 20 °C, 1 kHz with tan δ ≈0.61) is the highest in co‐doped ZnO ceramics reported so far. The colossal permittivity is brought out by the step‐like dielectric abnormities over which ɛ′ goes up steeply (≈10 1 –≈10 4 ) resulting from the mix‐valent ions of Fe 2+ /Fe 3+ , while the grain boundaries tend to make the dominant contribution at elevated temperature above the step‐like abnormity. The defect‐dipole (Li + –Fe 3+ ) can localize the electrons to a certain extent in the ZnO matrix inducing effective suppression of the dielectric loss. The sample FL‐0.01 exhibits the optimal colossal dielectric property and as x goes up further, the dielectric loss tends to increase obviously. This work provides a new routine to design optimal colossal dielectric materials and related devices for research and applications.