Colossal Dielectric Behavior and Dielectric Relaxation of (Li, Fe) Co‐Doped ZnO Ceramics. Issue 6 (16th April 2018)

• Record Type: Journal Article
• Authors: Wu, You; Li, Jun; Bai, Han; He, San; Hong, Yang; Shi, Kouzhong; Zhou, Zhongxiang
• Is Part Of: Physica status solidi. Volume 12:Issue 6(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-04-16
• Subjects: colossal dielectric constant -- defect‐dipole -- dielectric relaxation -- mix‐valent ions; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201800126
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : The co‐doped ceramics (Fe0.5 Li0.5 ) x Zn1− 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. Abstract : The ceramics (Fe0.5 Li0.5 ) x Zn1− x O ( x = 0.005, 0.01, 0.015) are prepared to investigate the colossal dielectric constant (CDC) property (ɛ′ ≈ 2.05 × 10 4 at 20 °C, 1 kHz with tanδ ≈ 0.61), resulting from step‐like dielectric abnormities by mix‐valent ions of Fe 2+ /Fe 3+, while the space charges in grain boundaries tend to make the dominant contribution at elevated temperature.