The formation of dimer and trimer aggregates in Sr-doped NaCl crystals

Dubiel, M.; Berg, Gunnar; Fröhlich, F.

doi:10.1002/pssa.2210550116

Cited by 15 publications

(5 citation statements)

References 16 publications

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“…The formed positive and negative vacancies can form vacancy-vacancy pairs via coulombic interaction (Beniere and Rokbani 1977), resulting in more and more [I-V] dipoles. These [I-V] dipoles are favourable to formation of nn and nnn-dipoles as reported earlier in alkali earth metal doped alkali halide crystals (Dubrie et al 1971) and more and more vacancy-vacancy pairs are created. These vacancies are favourable in formation of large aggregation of non-interacting clusters.…”

Section: Discussionsupporting

confidence: 70%

“…As the temperature is raised gradually, the second order precipitate dissociate and enter the crystal lattice and produce more and more vacancies in the extrinsic associate region [region III] and favour the formation of [I-V] dipoles and vacancy-vacancy pairs. Already some of the impurity ions entered the lattice at the time of growth only, so that it forms more and more dipoles and favour the formation of nn-dipoles and nnn-dipoles as well as vacancy pairs as reported earlier (Dubrie et al 1971). Due to formation of nn-and nnn-dipoles as well as vacancy-vacancy pairs, the concentration of cation vacancies are suppressed.…”

Section: Effect Of Impurity Concentrationmentioning

confidence: 61%

“…It is ascertained by the previous investigation that in alkali halide like KCl crystals doped with alkaline earth metals like Ca 2+ , Sr 2+ , Ba 2+ etc ions enter the crystal matrix by substituting a K + ion and creates a positive ion vacancy in its nearest neighbourhood for charge compensation (Dubrie et al 1971;Nadler and Rossel 1973;Saibabu 1995). The substituted ion behaves effectively positive and the positive vacancy site behaves as effectively negative, when these are not apart, then there will be a tendency for them to get paired up resulting in a neutral impurity-vacancy [I-V] dipoles.…”

Section: Discussionmentioning

confidence: 99%

“…Similarly when KCl crystals are doped with GdCl 3 impurity ion, the GdCl 3 is dissociated and enter in the crystal matrix as Gd 3+ and Cl -. When Gd 3+ enters the host crystal matrix, it substitutes a K + ion and for charge compensation two positive ion vacancies are created in its nearest neighbourhood (Dubrie et al 1971;Nadler and Rossel 1973;Saibabu 1995). Actually two positive ion vacancies are created in the vicinity of gadolinium ion which is surrounded by six cations.…”

Section: Discussionmentioning

confidence: 99%

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Study of effect of quenching and deformation on KCl: Gd3+ crystals by using conductivity measurements

2004

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The study of ionic conductivity vs reciprocal temperature of pure KCl and KCl crystal doped with 0⋅ ⋅1, 0⋅ ⋅3 and 0⋅ ⋅5 mole% gadolinium has been carried out in as grown, quenched from elevated temperatures (100, 350 and 500°C) and annealed at various timings i.e. 2-3 h and deformed by different percentages. The plots exhibit three well-known regions, II, III and IV (extrinsic regions). The intrinsic region I was not observed in the plots as the conductivity measurements were taken up to 575°C. From the analysis of these plots, activation energies for the migration of cation vacancy and the association of gadolinium ion with cation vacancy in the lattice of KCl crystals are calculated. These values are compared with previously reported values. Further, an attempt is made to explain the existence of oxidation state of gadolinium ion in + 3 state rather than in + 2 state as reported earlier. The variation in conductivity with effect of concentration of impurity ion, quenching and annealing and deformation with various percentages are explained on the basis of formation of impurity vacancy dipoles, vacancy-vacancy pairs (which appear in the form of precipitation), storage of cation vacancies in the form of defects, introduction of fresh dislocations, etc.

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Section: Discussionsupporting

confidence: 70%

Section: Effect Of Impurity Concentrationmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Study of effect of quenching and deformation on KCl: Gd3+ crystals by using conductivity measurements

2004

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“…The same relations can be also obtained directly from the equation system (2.2) by considering the equilibrium conditions [22]. It is interesting to remark here that, after inserting xsm and xgm (from (3.1)) into the law of mass conservation (2.4), we can also obtain (2.7).…”

Section: Analytical Solutionsmentioning

confidence: 60%

Aggregation Kinetics of Divalent Impurity–Vacancy Dipoles in Alkali‐Halide Matrix. I. Theoretical Approach

Poźzniak¹,

Berg²,

Galbatar³

1987

Physica Status Solidi (b)

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Approximate solutions of the equations describing the kinetics of reversible aggregation reactions of the divalent-impurity-vacancy dipoles in alkali halide crystals are obtained in which the dimers and trimers are assumed to be the only aggregation products. Using the solutions obtained a method is elaborated permitting to calculate the rate constants of individual reactions on the basis of the knowledge of the time evolution of the dipole concentration.Fur die Gleichungen, die die Kinetik dcr reversiblen Zustandsreaktionen der Dipole (Zweiwertige-Storstellen-Leerstellen) in Alkalihalogenidkristallen beschreiben, werden NLherungslosungen erhalten, fur die angenommen wird, da13 die Dimere und Trimere die eineigen Aggregationsprodukte darstellen. Mit den erhaltenon Losungen wird eine Methode erarboitet, die es erlaubt, die Ratenkonstanten der individuellen Reaktionen auf der Grundlage der zeitlichen Entwicklung der Dipolkonzentration zu berechnen.

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Kinetics of impurity particles in low-temperature matrices

Tishcheneo¹

1984

Phys. Stat. Sol. (a)

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The correlation between impurity atom diffusion coefficients and the parameters of interaction potentials of impurities with low-temperature matrix particles is established. The kinetics of the impurity particles in such a system is investigated and the possibility for obtaining information both on the diffusion coefficients and interatomic interaction potential parameters from the spectroscopic data is shown. The thermal conditions of the system are studied, that made it possible to determine the limits with respect t o thermal instability as well as temperatures and size of the matrix.T the crystal temperature in energy units. Here Ed is dependent on the parameters of l) P1. im. Kurchatova, 123 182 Moscow, USSR.

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The formation of dimer and trimer aggregates in Sr-doped NaCl crystals

Cited by 15 publications

References 16 publications

Study of effect of quenching and deformation on KCl: Gd3+ crystals by using conductivity measurements

Study of effect of quenching and deformation on KCl: Gd3+ crystals by using conductivity measurements

Aggregation Kinetics of Divalent Impurity–Vacancy Dipoles in Alkali‐Halide Matrix. I. Theoretical Approach

Kinetics of impurity particles in low-temperature matrices

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