Browsing by Author "Şabikoǧlu I."

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    Absorption and photoluminescence spectroscopy of Er 3+-doped SrAl 2O 4 ceramic phosphors
    (2012) Ayvackl M.; Khatab A.; Ege A.; Şabikoǧlu I.; Henini M.; Can N.
    A spectroscopic characterization of Er 3+-doped SrAl 2O 4 phosphor materials synthesized by a solid-state reaction method with Er concentrations varying from 0.1 to 1 mol% has been performed by studying photoluminescence (PL) in the temperature range 10 to 360K and absorption spectra. PL signals containing five emission bands at 1492, 1529, 1541, 1558, and 1600nm, respectively, have been observed at room temperature for Er 3+ transitions in the near infrared region. The samples exhibit a main luminescence peak at 1.54 μm, which is assigned to recombination via an intra-4f Er 3+ transition. Sharp bands centered at around 378, 488, 521, 651, 980, 1492, and 1538nm in the absorption spectra can be associated with transitions from 4I 15/2 level to 2H 9/2, 4F 7/2, 2H 11/2, 4F 9/2, 4I 11/2, 2H 11/2, and 4I 13/2 levels, respectively. The sharp emission peaks and excellent luminescence properties show that SrAl 2O 4 is a suitable host for rare-earth-doped phosphors, which may be suitable for optical applications. © 2012 Taylor & Francis.
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    Synthesis of Eu and Dy doped Sr3B2SiO8 using solid state reaction and investigation of radio and photoluminescence properties of these materials
    (2013) Şabikoǧlu I.
    Sr3B2SiO8 host material doped with separately Eu3+, Dy3+ synthesized by conventional solid state synthesis methods at 1100 °C. According to the results of XRD, samples have both of the Sr3B2SiO8 phase and the SrSiO3 phase (Multi-phase MP). Although there is significant amount of impurity concentration, expected energy transitions were obtained from the samples which are doped with Eu3+ and Dy3+. Both samples were performed to the radioluminescence (RL) and photoluminescence (PL) measurements. Measurement results, they were both in harmony with each other. Eu: Sr3B2SiO8 (MP) phosphor has 5D0 → 7Fj (j = 0, 1, 2, 3 and 4) transitions and Dy: Sr3B2SiO8 (MP) phosphor has 4F9/2 → 6HJ (j = 9/2, 11/2, 13/2 and 15/2) transitions. Dy:Sr3B2SiO8 (MP) phosphor synthesized by conventional solid state synthesis method and the RL and PL properties were examined for the first time. © 2012 Elsevier B.V. All rights reserved.
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    FTIR and VSM properties of samarium-doped nickel ferrite
    (World Scientific Publishing Co. Pte Ltd, 2014) Şabikoǧlu I.; Parali L.
    Nickel Ferrite (NiFe2O4) doped with Samarium (Sm) (0.2, 0.3, 0.4, 0.5 mol.%) was prepared by the conventional solid-state reaction. The crystal structure, surface morphology, infrared spectrum of absorption, and magnetic properties of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and vibrating sample magnetometer (VSM). XRD patterns were indexed with inverse spinel cubic phase with the space group of Fd-3m of nickel ferrite. The average grain size was about 5-10 μm. FTIR spectral study on the NiFe2O4 ferrite phase was recorded between 350 cm-1 and 4000 cm-1. Two fundamental absorption bands of the ferrites were appeared at 450 cm-1 and 1000 cm -1 characteristic of metal vibrations. VSM measurements show that the NiFe2O4 doped with Sm 0.3% has the highest value of saturation magnetization. It is also easily demagnetized due to the low value of coercivity field it has. Both NiFe2O4 doped with Sm 0.2 mol.% and 0.4 mol.% materials have same values of coercivity field. However, NiFe2O4 doped with Sm 0.4 mol.% material has the comparatively high value of saturation magnetization than NiFe2O 4 doped with Sm 0.2%, also this material was hardly demagnetized, and has highest coercivity field. © 2014 World Scientific Publishing Company.