Badalyan, A G and Azzoni, C B and Galinetto, P and Mozzati, M C and Trepakov, V A and Savinov, M and Deyneka, A and Jastrabik, L and Rosa, J (2007) Impurity centers and host microstructure in weakly doped SrTiO3:Mn crystals: new findings. Journal of Physics: Conference Series, 93 . 012012 (8pp).
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Official URL: http://stacks.iop.org/1742-6596/93/012012
Electron paramagnetic resonance (EPR), optical absorption and low-frequency (100 Hz − 1 MHz) dielectric permittivity investigations on Verneuil as-grown and reduced SrTiO3:Mn (0.1% at.) crystals were carried out to establish connection between the structure of Mn doping related centers and the SrTiO3 dielectric properties. At room temperature the EPR spectrum of as-grown crystals evidences isotropic Mn4+ and Mn2+ centers. The Mn2+/Mn4+ ratio increases, according to the EPR spectra, by decreasing the temperature and the signals intensity of both centers strongly decreases approaching T~120 K. Such behavior is attributed to antiferromagnetic interaction in MnO and MnO2 nano-clusters. Also the dielectric permittivity behavior evidences samples inhomogeneity as well as absence of pronounced dielectric relaxation in as grown crystals. In reduced crystals the Mn2+ concentration increases and the dielectric relaxation emerges evidencing a polaronic-related nature of dipole reorientations.
|Deposited By:||Prof. Alexey Ivanov|
|Deposited On:||06 Aug 2009 11:04|
|Last Modified:||06 Aug 2009 11:32|
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