Enhanced Ferroelectric Property of Manganese Doped Lead-free (K_0.5Na_0.5)NbO₃ Ceramics

Abstract

Lead free bulk ceramics manganese doped ceramics (1-x)(K_0.5Na_0.5)NbO₃-xMnO₂ (0 ≤ x ≤0.8 mol%, KNN-Mn-x) were prepared by a conventional solid-state sintering technique. Effects of manganese on the phase structure, morphologies and electrical properties of KNN ceramics were investigated. Mn-doped ceramics exhibited good crystallization and improved ferroelectric property. The XRD results showed the single phase perovskite structure was obtained in Mn-doped KNN ceramics. For KNN-Mn-x ceramics with x = 0.4 mol.%, excellent ferroelectric property was obtained: high remanent polarization P_r = 28.3 μC/cm² and low coercive field E_c = 13.7 kV/cm, which should be attributed to the single phase perovskite structure and the existence of a morphotropic phase boundary (MPB).

Keywords:

• Potassium sodium niobate
• manganese doping
• electrical properties
• perovskite structure