High-Frequency EPR Analysis of MnO₂-Doped [Bi_0.5Na_0.5]TiO₃-BaTiO₃Piezoelectric Ceramics – Manganese Oxidation States and Materials ‘Hardening’

Enhanced piezoelectric properties of Mn‐modified Bi5Ti3FeO15 for high‐temperature applications

“…The results indicate that BTF‐4Mn exhibits a higher insulation resistivity, but the exact mechanism of the resistivity increase by the Mn doping is unclear. The resistivity increase by Mn doping has also been observed in Mn‐modified BLSF CaBi 4 Ti 4 O 15 and other Mn‐modified perovskite‐structured systems, such as (Bi 0.5 Na 0.5 )TiO 3 ‐BaTiO 3 , (K x Na 1‐ x )NbO 3 , and Pb(Zr x Ti 1‐ x )O 3 . It has been attributed to the oxygen vacancies generated by the added acceptor Mn ions, which make the material “harder.” Therefore, in this study, the resistivity increase in BTF by the Mn doping can be attributed to the oxygen vacancies generated by the added acceptor Mn ions.…”

“…It has been attributed to the oxygen vacancies generated by the added acceptor Mn ions, which make the material “harder.” Therefore, in this study, the resistivity increase in BTF by the Mn doping can be attributed to the oxygen vacancies generated by the added acceptor Mn ions. Although manganese is present as tetravalent Mn 4+ in MnO 2 oxide doping, after sintering, an effective equilibrium of divalent Mn 2+ is achieved, confirmed by high‐frequency electron paramagnetic resonance . The activation energy E a was calculated according to the Arrhenius law, ρ = ρ 0 exp(− E a / kT ), where ρ 0 is an exponential factor, E a is the activation energy, k is the Boltzmann constant and T is the thermodynamic temperature.…”

Electric-field–temperature phase diagram of the ferroelectric relaxor system (1 − x)Bi1/2Na1/2TiO3 − xBaTiO3 doped with manganese

“…Peaks in field-dependent poling and switching currents indicate the formation or decay of domain structures, while field-dependent measurements of the permittivity and piezoelectric coefficient serve to further identify the domain state at given external conditions. Mn-doping with a level of 0.5 mol%, introduced as acceptor Mn 3þ on the B-site, 37 was employed to reduce the conductivity 38 and grasp temperature dependent effects without artifacts from leakage currents.…”

Enhanced ferroelectric and piezoelectric response in Mn-doped Bi0.5Na0.5TiO3–BaTiO3 lead-free film by pulsed laser deposition

“…The Mn doping has been found to be effective to improve the piezoelectric and electromechanical properties in bulk counterparts [15]. Multivalent Mn ions may coexist in the films and possibly occupy either A-or B-site, which exhibited combined "softening" and "hardening" effects simultaneously, resulting in the enhanced piezoelectric response, ferroelectric polarization, and dielectric properties [14,27].…”