Journal of Materials Science Materials in Electronics, 2010
X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electron paramagnetic resonance (E... more X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electron paramagnetic resonance (EPR) spectroscopies have been employed to investigate the xGd2O3 · (95 − x)[2Bi2O3 · B2O3] · 5V2O5 glass system, with 0 ≤ x ≤ 25 mol%. The glass samples have been prepared by melting at 1,100 °C for 10 min followed by rapid cooling at room temperature. The structure of samples was analyzed by means of XRD. The pattern obtained did not reveal any
Journal of Optoelectronics and Advanced Materials, Sep 1, 2008
ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 < x < 40 mol%,... more ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 < x < 40 mol%, have been obtained and investigated by magnetic susceptibility measurements. Magnetic susceptibility data evidenced both Eu3+ and Eu2+ valence states as simultaneously present in the bismuth-borate glass matrix. These ions are involved in negative superexchange interactions, being antiferromagnetically coupled. The content of Eu3+ and Eu 2+ ions was determined from the experimental values of the effective magnetic moments for all samples.
Journal of Optoelectronics and Advanced Materials, Dec 1, 2008
... The Van Hove singularities corresponding to bismuth and boron orbital derived states are clef... more ... The Van Hove singularities corresponding to bismuth and boron orbital derived states are cleft suggesting that there are strong boron–oxygen and bismuth ... J, Barone V, Cossi M, Cammi R, Mennucci B, Pomelli C, Adamo C, Clifford S, Ochterski J, Pet-ersson GA, Ayala PY, Cui Q ...
Journal of Optoelectronics and Advanced Materials, Sep 1, 2008
ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3... more ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3] (O≤ × ≤30mol%) system. The variations observed in the FTIR spectra were correlated with density measurement. The structural results show that these glasses present characteristic tellurium and boron environments which vary with chemical composition of gadolinium oxide. So that at a small content of gadolinium oxide increase the intensity bands assigned to the [TeO4] and [BO4] units, thus transform the [BO4] units into the [BO3] units and changes progressively the coordination of tellurium from 4 through 3+1 to 3 when the quantity of gadolinium ions increases.
The structures of novel bismuth-lead-silver glasses and glass ceramics doped with neodymium ions ... more The structures of novel bismuth-lead-silver glasses and glass ceramics doped with neodymium ions were studied by X-ray diffraction (XRD) and FTIR spectroscopy. FTIR spectroscopy data show that BiO 3, BiO 6, PbO 3 and PbO 4 are the most important structural units in the studied systems. These data also made it possible to obtain essential information concerning the arrangement of the structural units in the studied glasses and glass ceramics. XRD diffraction shows the presence of Bi 2O 3 and PbO 1.44 crystalline phases for the samples heat treated at 600 °C for 20 h.
X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been employed to ... more X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been employed to investigate the (Fe2O3)x·(B2O3)(60-x)·(ZnO)40 samples, with 0 <= x <= 20 mol%. The samples have been prepared by melting at 1100 °C for 10 minutes followed by rapid cooling at room temperature. The structure of samples was analyzed by means of XRD. XRD pattern show that the sample without iron ions and the samples contained 3 and 5 mol% were glasses. For samples contain 10, 15 and 20 mol% Fe2O3 it obtains glass ceramics. These glass ceramics contains a unique crystalline phase, zinc ferrite (ZnFe2O4), embedded in an amorphous matrix. FTIR spectroscopy data suggest that for the glass samples the iron ions play the network modifier role. These data show that the glass network consists of BO3 and BO4 structural units. For glass ceramics samples FTIR spectra show characteristic bands of ZnFe2O4.
ABSTRACT The NiZr master alloys were prepared by arc melting using high purity metals in a Ti-get... more ABSTRACT The NiZr master alloys were prepared by arc melting using high purity metals in a Ti-gettered argon atmosphere. The alloys were melted several times in order to improve homogeneity. The ingots were induction-melted under a high-purity argon atmosphere in a quartz tube and a graphite crucible, injected through a nozzle onto a Cu wheel to produce rapidly solidified amorphous ribbons. The characterization of the amorphous ribbons was done by X-ray diffraction, DSC analysis and tensile tests. The crystallization of amorphous Ni64Zr36 alloy has been studied with the help of non-isothermal scanning experiments in a differential scanning calorimeter. The thermograms at different scanning rates show a two-step crystallization. To determine the activation energy, the methods of Kissinger, Ozawa and Boswell are used starting from the shift of the peaks (Tp) according to the heating rate.
ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3... more ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3] (O≤ × ≤30mol%) system. The variations observed in the FTIR spectra were correlated with density measurement. The structural results show that these glasses present characteristic tellurium and boron environments which vary with chemical composition of gadolinium oxide. So that at a small content of gadolinium oxide increase the intensity bands assigned to the [TeO4] and [BO4] units, thus transform the [BO4] units into the [BO3] units and changes progressively the coordination of tellurium from 4 through 3+1 to 3 when the quantity of gadolinium ions increases.
ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 &lt; x &lt; 40 mol%,... more ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 &lt; x &lt; 40 mol%, have been obtained and investigated by magnetic susceptibility measurements. Magnetic susceptibility data evidenced both Eu3+ and Eu2+ valence states as simultaneously present in the bismuth-borate glass matrix. These ions are involved in negative superexchange interactions, being antiferromagnetically coupled. The content of Eu3+ and Eu 2+ ions was determined from the experimental values of the effective magnetic moments for all samples.
ABSTRACT Lead-bismuthate glasses with cerium and erbium ions have been prepared and investigated ... more ABSTRACT Lead-bismuthate glasses with cerium and erbium ions have been prepared and investigated by X-ray photoelectron spectroscopy (XPS). The Pb 4f, Bi 4f, O 1s, Er 4p, Ce 3d and Ce 4d binding energies have been measured in order to clarify the electronic structure of oxide glasses. The asymmetric Pb 4f and Bi 4f peaks for all studied glasses indicate the presence of PbOn and BiO n units. The O 1s spectrum was deconvoluted into two peaks and the variation of the ratio of the peak areas is discussed.
Journal of Materials Science Materials in Electronics, 2010
X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electron paramagnetic resonance (E... more X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electron paramagnetic resonance (EPR) spectroscopies have been employed to investigate the xGd2O3 · (95 − x)[2Bi2O3 · B2O3] · 5V2O5 glass system, with 0 ≤ x ≤ 25 mol%. The glass samples have been prepared by melting at 1,100 °C for 10 min followed by rapid cooling at room temperature. The structure of samples was analyzed by means of XRD. The pattern obtained did not reveal any
Journal of Optoelectronics and Advanced Materials, Sep 1, 2008
ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 &lt; x &lt; 40 mol%,... more ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 &lt; x &lt; 40 mol%, have been obtained and investigated by magnetic susceptibility measurements. Magnetic susceptibility data evidenced both Eu3+ and Eu2+ valence states as simultaneously present in the bismuth-borate glass matrix. These ions are involved in negative superexchange interactions, being antiferromagnetically coupled. The content of Eu3+ and Eu 2+ ions was determined from the experimental values of the effective magnetic moments for all samples.
Journal of Optoelectronics and Advanced Materials, Dec 1, 2008
... The Van Hove singularities corresponding to bismuth and boron orbital derived states are clef... more ... The Van Hove singularities corresponding to bismuth and boron orbital derived states are cleft suggesting that there are strong boron–oxygen and bismuth ... J, Barone V, Cossi M, Cammi R, Mennucci B, Pomelli C, Adamo C, Clifford S, Ochterski J, Pet-ersson GA, Ayala PY, Cui Q ...
Journal of Optoelectronics and Advanced Materials, Sep 1, 2008
ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3... more ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3] (O≤ × ≤30mol%) system. The variations observed in the FTIR spectra were correlated with density measurement. The structural results show that these glasses present characteristic tellurium and boron environments which vary with chemical composition of gadolinium oxide. So that at a small content of gadolinium oxide increase the intensity bands assigned to the [TeO4] and [BO4] units, thus transform the [BO4] units into the [BO3] units and changes progressively the coordination of tellurium from 4 through 3+1 to 3 when the quantity of gadolinium ions increases.
The structures of novel bismuth-lead-silver glasses and glass ceramics doped with neodymium ions ... more The structures of novel bismuth-lead-silver glasses and glass ceramics doped with neodymium ions were studied by X-ray diffraction (XRD) and FTIR spectroscopy. FTIR spectroscopy data show that BiO 3, BiO 6, PbO 3 and PbO 4 are the most important structural units in the studied systems. These data also made it possible to obtain essential information concerning the arrangement of the structural units in the studied glasses and glass ceramics. XRD diffraction shows the presence of Bi 2O 3 and PbO 1.44 crystalline phases for the samples heat treated at 600 °C for 20 h.
X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been employed to ... more X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been employed to investigate the (Fe2O3)x·(B2O3)(60-x)·(ZnO)40 samples, with 0 <= x <= 20 mol%. The samples have been prepared by melting at 1100 °C for 10 minutes followed by rapid cooling at room temperature. The structure of samples was analyzed by means of XRD. XRD pattern show that the sample without iron ions and the samples contained 3 and 5 mol% were glasses. For samples contain 10, 15 and 20 mol% Fe2O3 it obtains glass ceramics. These glass ceramics contains a unique crystalline phase, zinc ferrite (ZnFe2O4), embedded in an amorphous matrix. FTIR spectroscopy data suggest that for the glass samples the iron ions play the network modifier role. These data show that the glass network consists of BO3 and BO4 structural units. For glass ceramics samples FTIR spectra show characteristic bands of ZnFe2O4.
ABSTRACT The NiZr master alloys were prepared by arc melting using high purity metals in a Ti-get... more ABSTRACT The NiZr master alloys were prepared by arc melting using high purity metals in a Ti-gettered argon atmosphere. The alloys were melted several times in order to improve homogeneity. The ingots were induction-melted under a high-purity argon atmosphere in a quartz tube and a graphite crucible, injected through a nozzle onto a Cu wheel to produce rapidly solidified amorphous ribbons. The characterization of the amorphous ribbons was done by X-ray diffraction, DSC analysis and tensile tests. The crystallization of amorphous Ni64Zr36 alloy has been studied with the help of non-isothermal scanning experiments in a differential scanning calorimeter. The thermograms at different scanning rates show a two-step crystallization. To determine the activation energy, the methods of Kissinger, Ozawa and Boswell are used starting from the shift of the peaks (Tp) according to the heating rate.
ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3... more ABSTRACT Structural studies were investigated of glasses in the xGd 2O3.(100-x) [0,6TeO2·0,4B 2O3] (O≤ × ≤30mol%) system. The variations observed in the FTIR spectra were correlated with density measurement. The structural results show that these glasses present characteristic tellurium and boron environments which vary with chemical composition of gadolinium oxide. So that at a small content of gadolinium oxide increase the intensity bands assigned to the [TeO4] and [BO4] units, thus transform the [BO4] units into the [BO3] units and changes progressively the coordination of tellurium from 4 through 3+1 to 3 when the quantity of gadolinium ions increases.
ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 &lt; x &lt; 40 mol%,... more ABSTRACT Glasses of the xEu2O3-(100-x)[4Bi2O 3·-B2O3] system, with 0 &lt; x &lt; 40 mol%, have been obtained and investigated by magnetic susceptibility measurements. Magnetic susceptibility data evidenced both Eu3+ and Eu2+ valence states as simultaneously present in the bismuth-borate glass matrix. These ions are involved in negative superexchange interactions, being antiferromagnetically coupled. The content of Eu3+ and Eu 2+ ions was determined from the experimental values of the effective magnetic moments for all samples.
ABSTRACT Lead-bismuthate glasses with cerium and erbium ions have been prepared and investigated ... more ABSTRACT Lead-bismuthate glasses with cerium and erbium ions have been prepared and investigated by X-ray photoelectron spectroscopy (XPS). The Pb 4f, Bi 4f, O 1s, Er 4p, Ce 3d and Ce 4d binding energies have been measured in order to clarify the electronic structure of oxide glasses. The asymmetric Pb 4f and Bi 4f peaks for all studied glasses indicate the presence of PbOn and BiO n units. The O 1s spectrum was deconvoluted into two peaks and the variation of the ratio of the peak areas is discussed.
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