Effect of electric field on optical properties of post gamma-irradiated lithium potassium sulphate crystals

• Published in: Materials letters 2001-10, Vol.51 (1), p.19-26
• Main Author: El-Muraikhi, M
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electric field; Electrooptical effects; Exact sciences and technology; Lithium potassium sulphate; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Post irradiation
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(01)00258-0

Irradiation of lithium potassium sulphate crystals (LiKSO 4) was carried out by 60Co-gamma rays at a dose 150 kGy. Post irradiation, external direct current (dc) electric field was applied perpendicular to ferroelastic plane. The field intensity was varied between 0 and 10 kV/cm. From measurement of ultraviolet (UV) absorption versus wavelength ( A( λ)), optical band gap under various field intensity were deduced with Mott's plot. The pronounced change in the optical parameters against the field intensity is observed at the range from 0 to 0.5 kV/cm. This was attributed to the better alignment of the dipoles in the direction of the applied field. The obtained results were explained according the biasing inner electric field produced by γ-radiation, and subsequently stabilized by the external electric field, indicating the presence of interband transitions in such crystals.