Browsing by Author "Tomov, V."

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center dot-ray induced effects in Sm-doped strontium borate glasses
(2013)
Marinova, V.
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Tomov, V.
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Chuang, C. I.
;
Lin, Y. C.
;
Lin, S. H.
Strontium borate glasses SrB4O7 doped with Sm ions are prepared by conventional melting-quenching method. The effect of center dot-ray irradiation on the glass samples is studied by measuring the absorption spectra and the photoluminescence. It is found that the center dot -ray irradiation caused partial reduction of Sm3+ to Sm2+ at room temperature. Borate framework is supposed to be responsible for the Sm3+ to Sm2+ transition.
Growth, composition, ferroelectric and magnetic properties of new multiferroic Pb3.3Mn4.8Ni1.1Ti0.56O15.3 single crystals
(2016-07)
Tomov, V.
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Rafailov, P. M.
;
Luo, Chih-Wei
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電子物理學系
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Department of Electrophysics
Multiferroic single crystals in the novel system Pb-Mn-Ni-Ti-O have been grown by the high temperature solution growth method. At room temperature the crystals are indexed in the hexagonal space group P6(3)cm. The dielectric and magnetic properties along with the temperature dependence of the c-lattice parameter have been studied in the temperature range 2 K - 500 ?. The magnetic measurements reveal a paramagnetic to antiferromagnetic phase transition around 48 K. The dielectric permittivity exhibits a maximum at 430 K, indicating ferroelectric to paraelectric phase transition. The temperature dependent Raman and XRD measurements around 430 K reveal an anomaly and abrupt change of the lattice parameter along the z-axis respectively, thus confirming the ferroelectric-to-paraelectric phase transition.