Browsing by Author "Bondar, D. S."
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Item Dielectric Properties of the Pb2MoO5 Crystals Irradiated with uv Light(Дніпровський національний університет імені Олеся Гончара, 2017) Volnyanskaya, I. P.; Trubitsyn, Mykhailo P.; Volnyanskii, Dmytro M.; Bondar, D. S.; Shvets, T. V.EN: The dielectric properties of the Pb2MoO5 crystals, exposed to UV light radiation (290 K), were studied. It was shown that UV irradiation led to appearance of permittivity maximum near 530 K (AC field frequency f=1 kHz). Heating up to 700 K resulted in thermal dissociation of the dipole complexes, induced by UV light irradiation and contributing to e peak. The magnitude of the e maximum increased with increasing time of UV light exposure and saturated for t>90 min. It is supposed that the observed anomaly of e is determined by dielectric response of (MoO3)- complexes. These centers arise when photoelectrons are trapped by molybdenum ions with oxygen vacancy VO in the nearest surroundings.Item Phenomena Induced by UV Irradiation in PbMoO4 Single Crystal(Taylor & Francis, 2020) Bochkova, T. M.; Trubitsyn, Mykhailo P.; Volnyanskii, M. D.; Bondar, D. S.; Volnyanskii, Dmytro M.EN: Electrical properties and optical absorption of PbMoO4 single crystal were studied after UV irradiation. Anomalies of permittivity ε and conductivity σ were detected and attributed to the dipole centers induced by UV light. It was proposed that dipole centers were created by photoelectrons trapped by Mo within oxygen tetrahedra distorted by an oxygen vacancy VO. At high temperatures conductivity was nearly insensitive to UV irradiation. Additional optical absorption was observed in PbMoO4 single crystal after UV irradiation. It was argued that transfer of photoelectrons from lead to molybdenum groups was responsible for the photochromic effect found.