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Effect of MnO 2 Addition on the Structure and Electrical Properties of Pb(Zn 1/3 Nb 2/3 ) 0.20 (Zr 0.50 Ti 0.50 ) 0.80 O 3 Ceramics

2004; Wiley; Volume: 87; Issue: 5 Linguagem: Inglês

10.1111/j.1551-2916.2004.00847.x

1551-2916

Yudong Hou, Mankang Zhu, Feng Gao, Hao Wang, Bo Wang, Hui Yan, Changsheng Tian,

Microwave Dielectric Ceramics Synthesis

Pb(Zn 1/3 Nb 2/3 ) 0.20 (Zr 0.50 Ti 0.50 ) 0.80 O 3 ceramics of pure perovskite structure were prepared by the two‐stage method with the addition of 0–3.0 wt% MnO 2 and their piezoelectric properties were investigated systematically. The MnO 2 addition influences in a pronounced way both the crystal structure and the microstructure of the materials. The materials are transformed from the tetragonal to the rhombohedral structure, and the grain size is enhanced when manganese cations are added. The distortion of crystal structure for samples with MnO 2 addition can be explained by the Jahn–Teller effect. The values of electromechanical coupling factor ( k p ) and dielectric loss (tan δ) are optimized for 0.5‐wt%‐MnO 2 ‐doped samples ( k p = 0.60, tan δ= 0.2%) and the mechanical quality factor ( Q m ) is maximized for 1.0‐wt%‐MnO 2 ‐doped samples ( Q m = 1041), which suggests that oxygen vacancies formed by substituting Mn 3+ and Mn 2+ ions for B‐site ions (e.g., Ti 4+ and Zr 4+ ions) in the perovskite structure partially inhibited polarization reversal in the ferroelectrics. The ceramics with 0.50–1.0 wt% MnO 2 addition show great promise as practical materials for piezoelectric applications.