کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1526893 | 1511852 | 2008 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Characterization of Mn2+ doped tetramethylammoniumtetrachlorozincate single crystal using EPR and optical absorption
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
مواد الکترونیکی، نوری و مغناطیسی
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چکیده انگلیسی
Studies of fine and hyperfine structures of paramagnetic resonance spectra in single crystals of Mn2+: tetramethylammoniumtetrachlorozincate are reported. As sufficient numbers of lines were not obtained at room temperature, measurements were done at liquid nitrogen temperature (77 K). The Mn2+ spin Hamiltonian parameters are evaluated employing a large number of resonant line positions observed for various orientations of the external magnetic field. The values of the zero field parameters that give good fit to the observed EPR spectra are obtained. The values of different parameters are: g = 1.9834 ± 0.0002, A = (105 ± 2) Ã 10â4 cmâ1, B = (100 ± 2) Ã 10â4 cmâ1, D = (349 ± 2) Ã 10â4 cmâ1, E = (106 ± 2) Ã 10â4 cmâ1 and a = (21 ± 1) Ã 10â4 cmâ1. The percentage of covalency of the metal-ligand bond has also been determined. From the optical absorption study, the lattice distortion is suggested. The observed bands are assigned as transitions from the 6A1g(S) ground state to various excited quartet levels of Mn2+ ion in a cubic crystalline field. The electron repulsion parameters (B and C) and crystal field parameters (Dq and α) providing a good fit to the observed optical spectra are evaluated and the values are: B = 737 cmâ1, C = 2322 cmâ1, Dq = 670 cmâ1 and α = 76 cmâ1. The considerable decrease in the values of B and C parameters from free ion values (B = 960 cmâ1, C = 3325 cmâ1) has indicated that there exists a fair amount of covalent bonding between the central metal ion and the ligand. On the basis of deviations Îg = g â 2.0023 it has been ascertained whether electrons are transferred to or from the central ion by the action of bonding.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Chemistry and Physics - Volume 108, Issues 2â3, 15 April 2008, Pages 257-262
Journal: Materials Chemistry and Physics - Volume 108, Issues 2â3, 15 April 2008, Pages 257-262
نویسندگان
Ram Kripal, Manju Maurya,