Seminar INFLPR
Miercuri, 22 Martie 2017, ora 11:15
Sectia Laseri, Sala de seminar
Title: „Boron-phosphate sol-gel thin films doped with dysprosium and therbium ions”
Prezinta: Sava B. A.
Rezumat :
Phosphate glasses doped with 1d, 3d, 5d elements or/and rare earth oxides were studied in the past decade for their optical, opto-magnetic and bio applications. Phosphate glasses show promising usefulness as fast ion conductors, waveguides, optical switches, fibers, etc. Nevertheless, the applications of these glasses are often hampered by their low chemical durability. The addition of trivalent oxides together with substitution of alkali oxides by divalent oxides can seriously improve their chemical durability.
The mechanical parameters, as hardness, Young’s modulus and fracture toughness, demonstrate higher values with the addition of B2O3. Rare-earth doping ions introduce interesting opto-electronic, luminescence and opto-magnetic properties. Our studies in past years aimed at the stabilization of phosphate glasses and improvement of their properties by using B2 O3 combined with ZnO or PbO. Vitreous materials which matrix comprises as network formers phosphorus and boron oxides, as modifiers and chemical durability increasers Al2O3 together with ZnO co-doped with Dy and Tb oxide were studied for opto-magnetic applications.
Thin nano-structured boro-phosphate glass films are obtained by sol-gel method using spin-coating technique at different times and speed. The speed of 1500 rot/min was chosen for best results obtaining. Since the thickness of the films influence the magneto-optical properties, ten layers were deposited on glass and silicon substrates. The sol-gel films were dried at several temperatures, between 150 and 800oC. The structure and properties of the obtained samples were analyzed by using Raman, FTIR and UV-Vis spectroscopy, thermal analysis and mechanical behavior at nano- and micro – scale under concentrated load action. The structure – properties correlation was studied by using XRD, XRF, SEM-EDS, and AFM measurements. The magneto- optical properties were analyzed using a modified Kerr device.
