Structural dependence of the microwave dielectric properties of Cr3+-substituted ZnGa2O4 spinel ceramics: crystal distortion and vibration mode studies

2019 ◽  
Vol 7 (27) ◽  
pp. 8261-8268 ◽  
Author(s):  
Xiaochi Lu ◽  
Zehui Du ◽  
Bin Quan ◽  
Wenjie Bian ◽  
Haikui Zhu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Short Range ◽  
Vibration Mode ◽  
Microwave Dielectric Properties ◽  
Structural Dependence ◽  
Microwave Dielectric ◽  
Short Range Ordering ◽  
Dielectric Performance ◽  
Octahedral Distortion

Establishment of a correlation between the crystal structure (octahedral distortion and short range ordering) and microwave dielectric performance of spinel structured Cr-ZGO.

Sc Modification Induced Short-range Ordering in ZnGa2O4 Spinel Leading to High Microwave Dielectric Performance

2020 ◽  
Author(s):  
xiaochi Lu ◽  
Bin Quan ◽  
Kailai Zheng ◽  
Peng Chu ◽  
Jian Wang ◽  
...  
Keyword(s):  
Short Range ◽  
Microwave Dielectric Properties ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Governing Factor ◽  
Short Range Ordering ◽  
Dielectric Performance ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Relationship

Abstract Sc3+ (0,0.1,0.3,0.5,0.7mol%) modified ZnGa2O4 (abbreviated Sc-ZGO) ceramics were synthesized by solid-state method. The relationship between microwave dielectric performance and bonds vibration of Sc-ZGO as a function of Sc3+ modification has been systematically investigated. With Sc3+ modification, the εr of Sc-ZGO ceramics keeps steady (~10). While the τf of Sc-ZGO shows linear correlation with Sc3+ concentration increasing from -71ppm/℃ to -39ppm/℃, and the Q×f value climbs up to a maximum value (5Sc-ZGO) and then ramp down. 5Sc-ZGO sintered at 1350oC for 2 h exhibits the best microwave dielectric properties with εr = 9.9, Q×f = 124,147 GHz, tanδ = 7.98×10-5, and τf = -56 ppm/°C (@9.9 GHz). Q×f value of Sc modified ZGO increased by almost 45% compared with normal spinel ZnGa2O4 ceramics. The enhancement of τf and Q×f on Sc modified ZnGa2O4 can be attributed to higher densification, however, further Raman and FT-IR analysis elucidated that short-range cation ordering degree is another governing factor. The influence of Sc3+ modification on ZnGa2O4 bonds vibration has been discussed in detail.

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