Вышедшие номера
Magnetic resonance in PbxNbyOz-ceramics as a system containing chemical fluctuation regions
Vikhnin V.S.1, Asatryan H.R.1, Zakharchenya R.I.1, Kutsenko A.B.1, Kapphan S.E.2
1A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia
2FB Physik, Universitat Osnabruck, Osnabruck, Germany
Email: hike.asatryan@mail.ioffe.ru
Выставление онлайн: 20 июля 2005 г.

The simulation of chemical fluctuation regions in the PMN-like relaxors by growth of the PbxNbyOz-ceramics was performed. Different PbxNbyOz-clusters (chemically and structurally) coexist in such a ceramics. Hole polarons and bi-polarons, "Cr3+ - two polaronic holes" paramagnetic complexes were considered for an explanation of EPR spectra in PbxNbyOz-ceramics. Dynamical averaging and light induced effects, and significant effects of reduction treatment giving a co-existence of Nb5+ and Nb3+ ions as well as of strong internal magnetic field were discovered in such a ceramics. The latter could be related to antiferromagnetic phase realization in PbxNbyOz-clusters containing high enough concentration of magnetic Nb3+ host lattice ions. Such a situation leads to antiferromagnetic resonance on Nb3+ ions as well as to EPR of Cr3+-related paramagnetic complexes in Nb3+-induced internal magnetic field. Charge transfer vibronic excitons (CTVE) in free and in CTVE-phase states were detected in PbxNbyOz-ceramics by photoluminescence studies. Supported in part by RFBR (03-02-17589), and by Programs "Low dimension quantum structures" and "Spin-dependent effects in solids and spintronics".