Stage I/2012
Preliminary study was done related to obtaining method, structure and properties of MVMOVPR
Design, performing and experimentation of the laboratory method to prepare MVMOVPR
optical quality alumino-phosphate glasses containing rare-earth oxides were prepared by wet chemical method
Bulk glasses with low defects (bubbles, inclusions, crystals, striations) were obtained by using Alcoa (import USA) melting crucibles by comparison with the glass obtained in crucibles type ICEM, Romania
SEM-EDX analysis (scanning electron microscopy, energy dispersive X-ray) revealed the presence of bubbles and micro-crystals in the bulk glass. Some of the crystals were identified as having the similar chemical composition to that of aluminum phosphite
EDX elemental maps showed a good chemical homogeneity of the doped phosphate glasses due both to the wet chemical method used to prepare the mixture of raw materials and to the homogenization program by mechanical stirring applied to the glass melt
A simple and efficient method used to assess the optical homogeneity and the remnant stress in the final glass was adapted; in order to establish the bubble and striae content, a method based on polarized light was applied.
The refractive index and optical dispersion were determined for several wavelengths in the visible domain
Characterizing procedures magnetic and magneto-optical properties of vitreous samples with rare earth ions
Information regarding the type of magnetic order and range of the magnetic moment of the rare-earth ions were obtained by magnetic susceptibility measurements, depending on temperature and field dependent magnetization respectively, at constant temperature. In all cases, we took into account the contribution of the vitreous matrix, doped with rare-earth ions, to the level of the magnetic signal
MOKE equipment was adapted (Magneto-Optical Kerr) for measurements of Faraday effect (measured by light transmission) by special mounting samples with and without magnetic field
A standard procedure for the measurement of magneto-optical effect in transmission geometry was established (set-up)
The dependence of the polarization vector rotation on the sample rotation angle around the wave vector (that was permenently mentained perpendicular on the sample plan) was noticed
Due to the optical anisotropy of the vitreous matrix (most likely induced by the specific conditions of preparation), it was found that a complete measurement must necessarily be polar, that is to be defined by the evolution of the Kerr angle against sample rotation angle.
The experimental conditions were determined to maximize the Kerr angle for a given sample. The Kerr angles depend sensitively on the sample homogeneity, so the purpose of the subsequent research reportswill have to consideras essential to prepare high homogeneous glass samples
Magnetic and magneto-optical measurements were performed on vitreous samples doped with rare-earth ions (Dy, Tb, Me, Pr). Conclusive results both with respect to the magnetic measurements and magneto-optical glasses were obtained for Tb and Dy doped glasses.
It was found that the magneto-optical properties of the obtained glasses are dependent on melting, stirring and annealing applied programs
The dissemination of the research results developed within Stage I of the project was done by publication of five articles in professional journals (ISI), submissionof four articles for publication in professional journals and presentation of six scientific papers at international events
Stage II/2013
Phosphate glasses doped with Eu3+, Dy3+ and Tb3+ have been prepared applying homogenization system by mechanical stirring of the vitreous melt
Undoped phosphate glass (reference glass) and La3+ replaced by Y3+ glass have been prepared in order to investigate magnetic and magneto-optical properties that will be correlated with those of Dy3+ and Tb3+ doped glasses
Optical measurements (optical homogeneity and remanent strains) have been performed on undoped glass and La3+ replaced by Y3+ glass
A theoretical model was elaborated to establish the rotation of the polarization plan due to the remnant strains (birefringence) that will be verified by magnetic measurements
Approach of two complementary measurement methods: optical homogeneity measured by polarimetry and, respectively, interferometry (applied only after polarimetry)
Stage III/2014
Stage IV/2015