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High-field/high-frequency EPR of paramagnetic functional centers in Cu2+- and Fe3+-modified polycrystalline Pb[ZrxTi1-x]O-3 ferroelectrics

Copper(II)- and iron(III)-modified Pb[ZrxTi1-x]O-3 ferroelectrics were investigated by means of highfield/high-frequency EPR. The results obtained suggest that CU2+ and Fe3+ both substitute as acceptor centers for [ZrTi](4+). Whereas for the iron-doped system the charge compensating oxygen vacancies (VO) lead to the formation of charged (Fe'(Ti)- VO) defect associates, no such associates have been observed for the copper-modified system. As regards the morphotropic phase boundary, the model of a mesoscopic mixing of the pure-member phases has been refined to a picture in which a nanoscale composition distribution prevails.

PbTiO3 single-crystals; electron-spin-resonance; lead titanate; ceramics; ESR; phase; valence; glasses; ions; Cr3+

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