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7126238 
Journal Article 
Effect of A-site La, Ba, and Sr doping on the threshold field and characteristic temperatures of PbSc0.5Nb0.5O3 relaxor studied by acoustic emission 
Dul'kin, E; Mihailova, B; Gospodinov, M; Roth, M; , 
2013 
Yes 
Journal of Applied Physics
ISSN: 0021-8979
EISSN: 1089-7550 
AMER INST PHYSICS 
MELVILLE 
WOS:000314746200063 
The behavior of the temperature of the dielectric-permittivity maximum T-m, the intermediate temperature T*, and the Burns temperature T-d in stoichiometric PbSc0.5Nb0.5O3 (PSN) as well as in PSN heavily doped on the A-site by La (PSN-La), Ba (PSN-Ba), and Sr (PSN-Sr) was studied by means of acoustic emission (AE) under an external dc electric field (E). For all compounds, T-m exhibits a non-trivial behavior when applying E, namely, it initially decreases with the increase of E, attain a minimum at a threshold field E-th, ranging from 0.55 kV/cm for PSN to 0.25 kV/cm for PSN-Sr, and then T-m starts to increase with further increase of E. The minimum of T-m is accompanied by a pronounced maximum of the AE count rate (N) over dot, which at E-th varies from 10.0 s(-1) to 3.0 s(-1) for all the compounds, respectively. The similarities and difference between PSN, PSN-Ba, PSN-La, and PSN-Sr with respect to E-th, the (N) over dot, and the normalized AE parameter eta are discussed from the viewpoint of three mechanisms: (i) chemically induced random local electric fields due to the extra charge on the A-site ion, (ii) disturbance of the system of stereochemically active lone-pair electrons of Pb2+ by the isotropic outermost electron shell of the substituting ion, and (iii) change in the tolerance factor and elastic fields related to the larger ionic radius of the substituting A-site ion. The characteristic temperatures T* and T-d also exhibit a non-trivial behavior under E, which is better pronounced for pure PSN than for the A-site-substituted PSN compounds. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790601]