INFLUENCE OF OXIDATION NUMBER OF MANGANESE ON MAGNETIC PROPERTIES OF LEAD FREE PIEZOELECTRIC BNT CERAMICS

摘要

Bi0.5Na0.5Ti1-xMnxO3 (x = 0.00, 0.02, 0.05, 0.10, 0.15) ceramics were synthesized by following a solid state reaction route, in which Mn4+ cations were supposed to substitute Ti4+ cations on the B-site. The site occupation and valence fluctuation of Mn2+/3+/4+ and Ti3+/4+ were characterized by X-ray Photoelectron Spectroscopy (XPS) and Electron Spin Resonance (ESR) for the BNTM-10 ceramics. Magnetization measurements were performed in a Superconducting Quantum Interference Device (SQUID) magnetometer under the condition of the field-cooled and zero field-cooled temperature for applied fields of 100 G and 1 kG. The results revealed a paramagnetic behaviour for the Mn-doped BNT at higher doping levels. This paramagnetism can be ascribed to the exchange of the coupling interaction between Mn3+/2+ ions and Ti4+ vacancy.