Nuclear-magnetic-resonance relaxation in glassy Cu-As-Se and Cu-As-S

Saleh, Zaki M.; Ga, Williams; Pc, Taylor

doi:10.1103/physrevb.47.4990

Cited by 10 publications

(3 citation statements)

References 26 publications

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“…This dependence is typical for chalcogenide and oxide glasses 8 and indicates the existence of very‐low‐frequency vibrational modes which are strongly coupled to nuclear spins and provide a dominant relaxation mechanism.…”

Section: Resultsmentioning

confidence: 83%

⁷⁵As NMR relaxation in glassy Ge–As–Se

Mammadov

Taylor

Reyes

et al. 2010

Physica Status Solidi (a)

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Phone: þ994 12 439 35 28, Fax: þ994 12 447 04 56We have used high magnetic fields to perform 75 As nuclear magnetic resonance (NMR) relaxation measurements in Ge-As-Se glasses. The spin-lattice relaxation time T 1 has been studied as a function of average coordination number, hri and temperature, T. We show that the relaxation time constant, T 1 , in this system can be a useful tool to probe rigidity of the glassy matrix. In the two extreme cases, zero-field nuclear quadrupole resonance (NQR) and high-field NMR, T 1 exhibits a similar dependence on the average coordination number. Namely, there is a region in this dependence at low hri values, where the spinlattice relaxation time does not change remarkably, followed by an increase in T 1 in glasses with hri more than 2.54. This transition can be correlated with the onset of rigidity percolation in the glassy matrix. The temperature dependence of the spinlattice relaxation rate is found in the form T À1 1 / T 2 . This behavior is typical for As and other nuclei in glasses at temperatures below 300 K and is indicative of Raman-like relaxation mechanism involving low-frequency modes. Spinecho intensity for Ge 2 As 2 Se 5 as a function of pulse separation exhibits exponential decay whose slope is the same as one of the average of the decay found from 75 As NQR measurements. This result indicates to the presence of indirect dipolar coupling of arsenic atoms in this composition.

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Section: Resultsmentioning

confidence: 83%

⁷⁵As NMR relaxation in glassy Ge–As–Se

Mammadov

Taylor

Reyes

et al. 2010

Physica Status Solidi (a)

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“…Details of the experimental setup have been published elsewhere. 13 The experiments utilized the spin echo method. A simple 90°-180°pulse sequence was used, where the pulses are separated by a time and the spin echo appears at time 2.…”

Section: Experimental Techniquesmentioning

confidence: 99%

Indirect (J) coupling of inequivalent As75 nuclei in crystalline and glassy As2Se3 and As2S3

Whitaker

Ahn

Hari

et al. 2003

The Journal of Chemical Physics

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We present the results of nuclear quadrupole resonance ͑NQR͒ measurements in crystalline and glassy As 2 Se 3 and As 2 S 3 . As a function of pulse separation, the decays of the NQR Hahn echoes following a 90°-180°pulse sequence exhibit damped oscillations superimposed on an exponential decay. These damped oscillations can be explained by an indirect coupling ͑J coupling͒ between two As nuclei through the polarized electrons on the chalcogen atom. Experimental values of the J couplings were obtained from the periods of the oscillations and calculations of the most probable transitions using second-order perturbation theory. The value estimated by this method for the 2 J( 75 As-S-75 As) in crystalline As 2 S 3 compares well with empirical estimates, which are obtained using an existing value of 2 J( 31 P-S-31 P) and known scalings with atomic number from the literature. Unfortunately, there is insufficient experimental data on 2 J(X -Se-X) couplings to make any empirical estimate of 2 J( 75 As-Se-75 As).

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“…In 1991 Ionov et al [34] demonstrated the electrical and electropho− tographic properties of selenium based metal containing multicomponent chalcogenide glass and outlined that these materials might be useful for electrophotographic and laser printer photoreceptors. In 1993 Saleh et al [35] have stu− died the nuclear magnetic resonance relaxation of Cu con− taining chalcogenide glasses. In 1996 Carthy et al [36] have introduced bismuth and antimony containing new class of multicomponent chalcogenide glasses.…”

Section: Global Status Of Metal Containing Chalcogenide Glassesmentioning

confidence: 99%

Recent advancement in metal containing multicomponent chalcogenide glasses

Singh

2012

Opto-Electronics Review

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Amorphous semiconductors or chalcogenide glasses are the key materials in modern optoelectronics to make comfortable life of our society. Understanding of physical properties (like microstructure, thermal, optical, electrical) of these materials is important for their different uses. Predominant study of physical properties of the metal containing multicomponent chalcogenide glasses have attracted much attention, due to their interesting variable features and wide range of structural network modifications. Structural modifications in these materials are usually described with respect to the values of structural units (or average coordination number). In significance to this, the present work demonstrates the chronological development in the field of chalcogenide glasses along with scanning electron microscopy (SEM) morphologies. Optical, electrical and thermal correlative properties of recent developed Se93−xZn2Te5Inx (0 ≤ x ≤ 10) metallic multicomponent chalcogenide glasses are discussed. Variation in SEM morphology, refractive index (n), extinction coefficient (K), optical energy band gap (Eg), electrical conductivity (σav), crystallization activation energy (Ec) and glass forming ability (GFA) with structural units of Se-Zn-Te-In glasses have been demonstrated in this study. Subjected materials thermal, optical and electrical parameters have been achieved higher and lower in a respective manner at the threshold structural unit value 〈r〉.

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Nuclear-magnetic-resonance relaxation in glassy Cu-As-Se and Cu-As-S

Cited by 10 publications

References 26 publications

⁷⁵As NMR relaxation in glassy Ge–As–Se

⁷⁵As NMR relaxation in glassy Ge–As–Se

Indirect (J) coupling of inequivalent As75 nuclei in crystalline and glassy As2Se3 and As2S3

Recent advancement in metal containing multicomponent chalcogenide glasses

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Nuclear-magnetic-resonance relaxation in glassy Cu-As-Se and Cu-As-S

Cited by 10 publications

References 26 publications

75As NMR relaxation in glassy Ge–As–Se

75As NMR relaxation in glassy Ge–As–Se

Indirect (J) coupling of inequivalent As75 nuclei in crystalline and glassy As2Se3 and As2S3

Recent advancement in metal containing multicomponent chalcogenide glasses

Contact Info

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⁷⁵As NMR relaxation in glassy Ge–As–Se

⁷⁵As NMR relaxation in glassy Ge–As–Se