کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7886743 | 1509787 | 2018 | 25 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structural, optical, and Raman studies of Gd doped sodium bismuth titanate
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
The effects of gadolinium (Gd) on lead free sodium bismuth titanate (Na0.5Bi0.5TiO3, NBT) ceramics are investigated. X-ray diffraction (XRD) studies indicate that perovskite phase (rhombohedral, R3c) is formed for all Gd doped NBT (Gdx:NBT) compositions (xâ¯=â¯0, 0.02, 0.04, 0.06, 0.08). XRD peak shifts to the higher angles for all compositions except for xâ¯=â¯0.08. Amphoteric nature of Gd in NBT sites are observed i.e., it occupies Bi-site up to xâ¯=â¯0.06 and then distributes to Ti-site. Octahedral distortion (c/a) increases in the range 0.02â¯â¤â¯xâ¯â¤â¯0.06 and then decreases. Raman spectra suggest that the introduction of Gd+3 ion induces structural changes without disturbing the long range order. The material can be readily excited using UV (360â¯nm) and shows emission peaks at ~592â¯nm and 687â¯nm. Optical property evaluation indicates that the lowest band gap (Eg = 2.78â¯eV) is observed at xâ¯=â¯0.08. When xâ¯>â¯0.04, the photoluminescence (PL) intensity decreases indicating the onset of concentration quenching. The critical energy distance (found to be 14â¯Ã
) and Dexter's theory based analysis indicate that concentration quenching is attributable to multipole-multipole (specifically dipole-dipole) interactions in the system. Commission International de Eclairage (CIE) chromatic color coordinates are reported for all doped systems; the observed patterns mirror PL analysis results. For instance, PL intensity shrinks beyond 4â¯at%; this corresponds to a regression in the CIE trajectory with respect to concentration.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 44, Issue 11, 1 August 2018, Pages 12118-12124
Journal: Ceramics International - Volume 44, Issue 11, 1 August 2018, Pages 12118-12124
نویسندگان
Santosh Behara, Lalitha Ghatti, Sivani Kanthamani, Malathi Dumpala, Tiju Thomas,