Naslov
Iron-oxygen vacancy defect association in polycrystalline iron-modified PbZrO3 antiferroelectrics : Multifrequency electron paramagnetic resonance and Newman superposition model analysis

Autori
Meštrić, Hrvoje ; Eichel, R.A. ; Dinse, K.P. ; Ozarowski, A. ; van Tol, J. ; Brunel, L.C. ; Kungl, H. ; Hoffmann, M.J. ; Schonau, K.A. ; Knapp, M. ; Fuess, H. ;

Izvornik
Physical Review B - Condensed Matter and Materials Physics (1098-0121) 73 (2006), 18; 184105-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
spin-hamiltonian parameters; neutron-difraction; crystal-structure; X-ray; ferroelectric phase; lead zirconate; thin-films; EPR; transition; centers

Sažetak
By utilizing multifrequency electron paramagnetic resonance (EPR) spectroscopy, the iron functional center in Fe3+-modified polycrystalline lead zirconate (PbZrO3) was studied. The single phase polycrystalline sample remained orthorhombic and antiferroelectric down to 20 K as confirmed by high-resolution synchrotron powder diffraction. The Fe3+ ions were identified as substituting for Zr4+ at the B-site of the perovskite ABO(3) lattice. Similarly as found for Fe3+:PbTiO3 [Mestric , Phys. Rev. B 71, 134109 (2005)], the value of the fine-structure (FS) parameter B-2(0) is only consistent with a model in which a charged (Fe-Zr(')-V-O(center dot center dot))(center dot) defect associate is formed. In contrast to a well defined iron functional center in lead titanate (PbTiO3) with FS parameters exhibiting variances of less than 3%, a strong broadening of the EPR powder pattern was observed in lead zirconate, indicating a much larger variance of FS parameters. It is suggested that the apparent broad distribution of fine-structure parameters arises from the system's capability to realize different oxygen vacancy positions in the first coordination shell around the iron site. This proposed model of a small number of distinct iron-oxygen vacancy sites is supported by the observation that corresponding B-2(0) and orthorhombic B-2(2) FS parameters of these sites are anticorrelated, a property not expected for random distributions of fine-structure parameters.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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