Publication Date:
2014-10-16
Description:
This work reveals that 0.5 mol. % manganese (Mn) doping in (Bi 0.5 Na 0.5 ) 1− x Ba x TiO 3 ( x = 0 and 0.075) solid solutions can increase structural thermal stability, depolarization temperature (T d ), piezoelectric coefficient ( d 33 ), and electromechanical coupling factor ( k t ). High-resolution X-ray diffraction and transmission electron microscopy reveal coexistence of rhombohedral (R) R3c and tetragonal (T) P4bm phases in (Bi 0.5 Na 0.5 ) 0.925 Ba 0.075 TiO 3 (BN7.5BT) and 0.5 mol. % Mn-doped BN7.5BT (BN7.5BT-0.5Mn). (Bi 0.5 Na 0.5 )TiO 3 (BNT) and BN7.5BT show an R − R + T phase transition, which does not occur in 0.5 mol. % Mn-doped BNT (BNT-0.5Mn) and BN7.5BT-0.5Mn. Dielectric permittivity ( ε ′) follows the Curie-Weiss equation, ε ′ = C/(T − T o ), above the Burns temperature (T B ), below which polar nanoregions begin to develop. The direct piezoelectric coefficient ( d 33 ) and electromechanical coupling factor ( k t ) of BN7.5BT-0.5Mn reach 190 pC/N and 47%.
Print ISSN:
0021-8979
Electronic ISSN:
1089-7550
Topics:
Physics
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