Sodium Nitrate Single Crystals Research Articles

A Comparative Investigation on the Structural Stability of the Single and Poly‐Crystalline Sodium Nitrate at Dynamic Shock Wave Loaded Conditions

AbstractExploration of the structural stability of the single and poly‐crystalline materials of solid‐state at high temperature and pressure is one of the basic research topics in the materials science branch. While the initial state of material undergoes change because of external factors, the functional properties of the material are usually significantly varied and hence, detailed investigations are highly required to better understand either change in properties or stability of materials with respect to their initial states. En route to this process, the crystallographic phase stability of sodium nitrate poly‐crystalline samples are studied at dynamic shocked conditions and the observed results are compared to the previously reported sodium nitrate single crystal. The structural stability profile of the test sample is assessed by X‐ray diffraction, Raman spectroscopic and optical spectroscopic techniques. Surface morphology features are obtained from the scanning electron microscopic (SEM) technique. The overall observation of the diffraction, spectroscopic and morphological analyses shows that the poly‐crystalline sodium nitrate sample has higher stability than that of the single crystal of sodium nitrate. The detailed interpretations are presented in the following sections.

Dynamic shock wave induced order-disorder type phase transition of sodium nitrate single crystal

In this letter, we demonstrate the dynamic shock wave induced order-disorder type phase transition exhibited by sodium nitrate single crystal and the results have been evaluated by diffraction, spectroscopic and microscopic techniques. The changeover of order into the disordered phase of NaNO3 crystal at shocked conditions is due to the occurrence of rotational disorder of planer anions (NO3).

Synthesis, growth, optical and third-order nonlinear optical properties of glycine sodium nitrate single crystal for photonic device applications

Glycine and its related compounds play a prominent role in the field of nonlinear optical studies and of fibre optical communication. In the present work, glycine sodium nitrate (GSN) crystal was grown using the method of slow evaporation method. The GSN crystal belongs to space group Cc in the monoclinic system. Using the FTIR spectrophotometer, the different functional groups have been qualitatively identified. A UV–Vis–NIR spectroscopy was used to record the optical absorption spectra, and the optical energy bandgap of GSN crystal is reported. The SHG conversion efficiency of GSN is determined by Kurtz and Perry technique. The Z-scan experiment was conducted to analyze GSN crystal for third-order NLO behavior and it is used to calculate the values of the nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility. Third-generation harmonic studies reveal that GSN is an excellent material useful in the fabrication of NLO devices due to its nonlinear response characteristics. The thermal stability of the grown crystal was determined through TG/DTA examination. Also photoconductivity studies confirm the negative photoconductive behavior of GSN and I–V characteristics measurement that have been carried out. The dielectric loss is significantly low and this supports defect-free growth of the crystal. These properties of GSN make it a good candidate in the fabrication of NLO devices.

Synthesis, Crystallization, Non Linear Optical and Anti-bacterial Activity of L-Alanine Sodium Nitrate Single Crystals

In this present work, L-Alanine Sodium Nitrate (LASN) single crystals were grown by spontaneous nucleation solution growth method. The cell parameters and crystalline structure of the LASN crystals were analysed using powder X-ray diffraction (PXRD) technique. The numerous functional groups in the LASN crystals were confirmed by FTIR analysis. SHG efficiency of the grown LASN crystal is 1.06 times superior to the reference crystalline material KDP. The antibacterial property of LASN crystals were assessed using by agar diffusion method.

Synthesis and thermal, optical, dielectric and mechanical properties of l-asparagine sodium nitrate single crystal

Single crystal of l-asparagine sodium nitrate (LASN) was grown from aqueous solution by room temperature solution growth technique. The grown crystal was characterized by single crystal X-ray diffractometry (XRD), FTIR and optical absorption spectrum. The micro hardness test of the sample revealed that the crystal belongs to the soft category of materials. The dielectric response of the crystal with varying frequencies was studied and reported. The thermal stability of the compounds has been determined by TG-DTA curves. The SHG relative efficiency of LASN crystal was found to be inferior than that of KDP.

Pyroelectric properties and conduction mechanism in solution grown glycine sodium nitrate single crystal

Nonlinear optical “glycine sodium nitrate” transparent single crystals were grown from aqueous solution by the solvent evaporation technique. The ferroelectric transition temperature was determined by dielectric measurement for GSN crystal. Temperature dependent pyroelectric coefficient and figure of merit were measured. The conduction mechanism of GSN crystal has been discussed. The lnσ−E1/2 characteristic in the high-field region supports dominating the Poole–Frenkel conduction while in the low field region; there are possibility of both Richardson–Schottky and Poole–Frenkel conduction mechanism. The activation energy of GSN crystal was found to be 0.58eV. A low value of dielectric constant and good value of the figure of merit suggest the GSN crystal more promising for IR sensing applications. Hardness value shows the stability of GSN crystal.

Evidence of sustained ferroelectricity in glycine sodium nitrate single crystal

The nonlinear optical single crystals of glycine sodium nitrate were grown by the slow evaporation method. XRD confirmed monoclinic structure. Thermal stability and melting point (225 °C) were investigated. The dielectric behaviour of the crystals in the frequency range 20 Hz–2 MHz at different temperatures is reported in which a ferroelectric to paraelectric phase transition at Tc = 56 °C is observed. The activation energies of GSN were found to be 3.615 eV, 0.593 eV and 0.0733 eV in three temperature regions of conductivity plot due to a hopping conduction mechanism. The crystal has shown high piezoelectric charge coefficient (d33) of 16 pC/N which is nearly double of observed value for γ-glycine single crystal. The spontaneous polarization Ps at room temperature was found to be 1.489 μC/cm2 at applied maximum field of 26 kV/cm (1.194 μC/cm2 at 12 kV/cm) and the pyroelectric coefficient was determined to be 400 μC/m2/°C. High value of squareness parameter (1.93) makes the GSN crystal suitable for switching applications. Detailed investigations of Ferro-/Piezoelectricity were observed for the first time in glycine sodium nitrate crystals which was found to preserve the ferroelectricity even after applying an electric field much higher than the saturation electric field (12–26 kV/cm). Application of GSN crystals as sensor, high power switch gears and storage memories has been established.

Investigations on the nucleation kinetics of bis glycine sodium nitrate

The nucleation parameters such as, energy per unit volume, radius of critical nucleus, critical free energy barrier, number of molecules in the critical nucleus and nucleation rate have been evaluated for bis glycine sodium nitrate single crystals. The interfacial energy of the solution at various temperatures has been estimated from existing solubility data. The metastable zone width and induction period measurements have been carried out experimentally.

On the white light luminescence induced by irradiation of sodium nitrate single crystals by 1064 nm laser light

A number of wide bandgap inorganic materials can be prepared so that stimulation with nanosecond pulses of near infra-red (1064 nm—Nd:YAG fundamental) generates intense, transient white light. This light can span from 300 to 900 nm. Here, we characterize this emission from single crystal NaNO 3 and show that it is due to optical breakdown in the bulk. We contrast the behavior and character of time resolved spectra of this bulk breakdown with surface breakdown and provide evidence of defect mediated processes being responsible for the observed avalanche. We also conclude that confinement of the avalanche is essential for the production of this broad banded luminescence.

Low‐Frequency Dielectric Response Function of Sodium Nitrate

AbstractThe far infrared and submillimeter dielectric function of sodium nitrate single crystal is determined by means of precise transmission spectroscopy (7 to 18 cm−1) and reflexion spectroscopy (10 to 600 cm−1) over the temperature range 20 to 275 °C, parallel and perpendicular to the crystallographic c‐axis. All the infrared active lattice modes are observed and their parameters calculated using the factorized form of the dielectric function. A relaxation is introduced to explain the low‐frequency dielectric function in the two directions.

Temperature dependence of the low-frequency reflectance spectrum of a sodium nitrate single crystal: Effect of the phase transition on the lattice modes parameters

Reflectivity of a single crystal sodium nitrate have been measured as a fonction of temperature and crystallographic orientations over a frequency region which spans all infrared active lattice modes. The data have been fitted with a series of five independent oscillators and an overdamped oscillator of A2u symmetry at temperatures between 250 and 276°C. None of them behaves as a soft mode. Our measurements show also the influence of the phase transition on the lattice modes parameters.

Study of evaporated replicas of sodium nitrate single crystals: V Sladek,Czech J Phys, B 21 (6), 1971, 693.

Study of evaporated replicas of sodium nitrate single crystals: V Sladek,Czech J Phys, B 21 (6), 1971, 693.

Study of evaporated replicas of sodium nitrate single crystals

Study of evaporated replicas of sodium nitrate single crystals

On the growth of large perfect crystals of sodium nitrate

The production of sodium nitrate single crystals (with dislocation density of about 10 5 cm -2) of 70 mm in diameter and 40 mm in length is described. The crystals were grown by the modified technique of Kyropulos, small plates of single crystal mica (of 20 mm in diameter) being used as a seed. The latter were glued to the cooler — a copper rod (water cooling was not needed). The growing of a crystal was accomplished in an aluminium crucible. The crystals obtained were completely transparent, without cracks, giving good cleavage planes. An etchant — zinc saturated ice acetic acid revealing both the grown-in dislocations and fresh one — is proposed.

The Magnetic Resonance of23Na Nuclei in Monocrystalline Sodium Nitrate

Accurate measurements have been made of the 23Na nuclear magnetic resonance spectrum of sodium nitrate single crystals from -190 °C to 300 °C in an applied magnetic field of 6000 Oe. The nuclear electric quadrupole coupling constant has a magnitude which is convenient for the separation of first- and second-order shifts of the resonance lines. The separation of the two satellite lines, to which second-order perturbations do not contribute, follows the theoretical first-order variation closely. The frequency of the central line, and the mean frequency of the satellite lines to which first-order perturbations do not contribute, accurately follow the theoretical behaviour using the parameters determined from the first-order examination. The magnitude and angular variation of the second moment of the central line at room temperature is in excellent agreement with the theory of Kambe and Ollom and provides the first experimental test of their theory. At all orientations of the crystal the second moment is approximately 10% smaller than would be expected if the quadrupole coupling constant were zero, when Van Vleck's expression would be applicable. The width of the line decreased over the range 200° to 280 °C to a small value; this reduction is ascribed to diffusion of the sodium ions. The quadrupole coupling constant was found to decrease by a factor of ten over the whole range of temperature, with a discontinuity in the temperature dependence at the second-order phase transition, 276 °C. This unusually large decrease is much greater than can be explained by the effects of lattice expansion or the tendency of the crystal structure to become somewhat more nearly cubic. The behaviour must clearly be associated with the changes in the crystal which lead to the second-order phase transition. Experimental information bearing on the nature of the phase transition is reviewed. It is shown that the evidence can be reconciled by a dynamic-disorder model in which the nitrate groups reorient about their threefold axes with increasing rapidity as the temperature rises. Although this motion does not become free it encourages the disordering of orientation of the nitrate groups leading to a phase-transition of the order-disorder type. This motion does not however directly account for the reduced electric field gradient experienced by the sodium nuclei. It is proposed that this reduction arises from the oscillation of the sodium ions predominantly in directions perpendicular to the triad axis of the unit cell, and that this motion is a secondary consequence of the mechanism of the phase transition. Calculations have been made of the electric field gradient, and these support the proposed mechanism of dynamic disorder.