Spectroscopic analysis and magnetic susceptibility of CuO–TeO2–V2O5 glasses

Yahia, I.S.; Saddeek, Yasser B.; Sakr, G.B.; Knoff, W.; Story, T.; Romčević, N.; Dobrowolski, W.

doi:10.1016/j.jmmm.2009.07.084

Cited by 33 publications

(8 citation statements)

References 45 publications

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“…In essence, the impurity may occupy suitable octahedral sites (e.g., the octahedral interstitial sites) capacious enough to accommodate it without breaking local stability for very low copper concentration (≈ 0.1% mol) at low temperature (77 K). Judging from the experimental EPR data [14,15] of the studied systems, the averageḡ ∼ 2.1 and the anisotropies (g // > g ⊥ > 2 and |A // | > |A ⊥ |) for g factors and hyperfine structure constants definitely indicate the impurity Cu 2 + occupying tetragonally elongated octahedral sites (e.g., octahedral interstitial sites), as supported by the extensive EPR studies for Cu 2 + in various tetragonally elongated octahedra (both crystalline [32][33][34][35][36] and amorphous [37][38][39][40][41][42] systems). Therefore, the impurity Cu 2 + may tend to occupy some octahedral sites available (e.g., the octahedral interstitial sites) in the studied systems and thus exhibit the tetragonally elongated [CuO 6 ] 10− units due to the JahnTeller distortions via the vibration interactions [11,16,43].…”

Section: Theory and Calculationssupporting

confidence: 59%

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu²⁺in crystalline and amorphous TeO₂and GeO₂

2014

Molecular Physics

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The spin Hamiltonian parameters (i.e., anisotropic g factors and hyperfine structure constants) and local tetragonal distortions for Cu 2 + in crystalline and amorphous TeO 2 and GeO 2 are theoretically investigated using the high-order perturbation formulas of these parameters for a tetragonally elongated octahedral 3d 9 cluster. The impurity Cu 2 + occupying the octahedral sites are found to experience the relative tetragonal elongation ratios of about 11.4% and 9.5% for crystalline TeO 2 and GeO 2 and 10.8% and 6.6% for amorphous TeO 2 and GeO 2 , respectively, along the C 4 axis due to the Jahn-Teller effect. This reveals the larger tetragonal elongation distortions for the Cu 2 + centres in crystalline than amorphous systems (especially TeO 2 ). The theoretical spin Hamiltonian parameters show good agreement with the experimental data. The results are discussed. IntroductionTeO 2 and GeO 2 containing copper show interesting thermal and conductive [1,2], mechanical [3], acousto-optic [4] and hyperspectral imaging [5], electronic [6], optical absorption [7-9] and photoluminescence properties [10]. Meanwhile, Cu 2 + impurities doped into crystals may be regarded as model systems due to the relatively simpler energy levels (only one ground state and one single excited state under ideal octahedral crystal-fields [11]) and have been an important topic of electron paramagnetic resonance (EPR) spectroscopic measurements [12,13]. EPR experiments were carried out for low concentration (0.1% mol) Cu 2 + doped crystalline and amorphous TeO 2 and GeO 2 , and the spin Hamiltonian parameters (i.e., anisotropic g factors g and g ⊥ and hyperfine structure constants A and A ⊥ ) were also measured at 77 K [14,15].As for the theoretical interpretation for the above experimental results, the previous analysis was generally unsatisfactory [14,15]. First, the simple second-order g formulas were adopted with various adjusted molecular orbital coefficients [14,15]. Moreover, local structures were not involved in the calculations. As a result, the calculated spin Hamiltonian parameters were not in good agreement with the observed values. In fact, the Jahn-Teller ion Cu 2 + may suffer the Jahn-Teller effect (i.e., the phenomenon of removal of degeneracy of energy levels via vibration interactions, resulting in lower symmetries and energies [11,16]) and thus bring forward modification in the local environments around the impurity as compared with the host cation sites.

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Section: Theory and Calculationssupporting

confidence: 59%

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu²⁺in crystalline and amorphous TeO₂and GeO₂

2014

Molecular Physics

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“…From the FT-IR spectra of glasses, the presence of IR vibrational peaks at 785-794 cm À1 indicates that there are isolated TeO 3 structural unit in the glass composition studied [35]. The presence of the Zn 2+ leads to the creation of TeO 3 and additional TeO 3+1 polyhedral [36] The addition Li 2 O on expanse of TeO 2 causes a decrease in the number of oxygen ions in the network [30] and breaks the Te-O-Te bonds in the trigonal [TeO 4 ] bipiramyds and forms [TeO 3 ] trigonal pyramid through TeO 3+1 along with non-bridging oxygens on the account of TeO 4 units. When the Li 2 O molar percentage increases substituting TeO 2 in the samples the bands of TeO 4 shift towards to higher wavenumbers.…”

Section: Infrared Spectral Studiesmentioning

confidence: 99%

“…The observed broadening of the bands in the spectra of the glasses may arise for two reasons. The first is the distribution of bond angles and bond lengths and fluctuations of the local electronic and atomic environments in the amorphous state [30]. The second reason is the overlapping of some individual bands with each other.…”

Section: Temperature (K)mentioning

confidence: 99%

Effect of lithium addition on thermal and optical properties of zinc–tellurite glass

Mohamed

Ahmad

Aly

2012

Journal of Alloys and Compounds

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“…Each individual band has two characteristic parameters; the center (C), which is related to some type of vibrations of a specific structural group and the relative area (A), which is proportional to the concentration of this structural group. A curve fitting process should be performed to extract such parameters [40,41]. Fig.…”

Section: Raman Spectral Studiesmentioning

confidence: 99%

Optical spectroscopy, optical conductivity, dielectric properties and new methods for determining the gap states of CuSe thin films

Sakr

Yahia

Fadel

et al. 2010

Journal of Alloys and Compounds

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167

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Spectroscopic analysis and magnetic susceptibility of CuO–TeO2–V2O5 glasses

Cited by 33 publications

References 45 publications

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu²⁺in crystalline and amorphous TeO₂and GeO₂

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu²⁺in crystalline and amorphous TeO₂and GeO₂

Effect of lithium addition on thermal and optical properties of zinc–tellurite glass

Optical spectroscopy, optical conductivity, dielectric properties and new methods for determining the gap states of CuSe thin films

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Spectroscopic analysis and magnetic susceptibility of CuO–TeO2–V2O5 glasses

Cited by 33 publications

References 45 publications

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu2+in crystalline and amorphous TeO2and GeO2

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu2+in crystalline and amorphous TeO2and GeO2

Effect of lithium addition on thermal and optical properties of zinc–tellurite glass

Optical spectroscopy, optical conductivity, dielectric properties and new methods for determining the gap states of CuSe thin films

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Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu²⁺in crystalline and amorphous TeO₂and GeO₂

Theoretical investigations of the spin Hamiltonian parameters and local tetragonal distortions for Cu²⁺in crystalline and amorphous TeO₂and GeO₂