Growth and characterization of NixZn1−xSO4·7H2O single crystals

• Large and good quality single crystals have been successfully grown.
• Tuning optical, mechanical and electrical properties is understood as possible.
• The electrical conduction could be understood as due to proton transport.
• Equimolar mixed crystal is found as promising NLO and low- εr material.

NiSO4·7H2O (morenosite) and ZnSO4·7H2O (goslarite) are hydrogen bonded crystals having wide applications in various fields. In an attempt to understand the formation and properties of mixed crystals based on NiSO4·7H2O and ZnSO4·7H2O, we have grown by the free evaporation method at room temperature and characterized NixZn1−xSO4·7H2O single crystals (with x having the values 0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0). The grown crystals were characterized chemically and structurally by carrying out density, X-ray powder diffraction, and atomic absorption and Fourier transform infrared spectral measurements. The grown crystals exhibit good optical transparency in the wavelength range 210–1100 nm. The second harmonic generation measurements indicate a maximum efficiency for the mixed crystal with x = 0.5. Results of microhardness measurements follow the normal indentation size effect. Electrical (AC and DC) measurements indicate that the grown crystals exhibit a normal dielectric behavior and the electrical conduction is understood to be due to the protonic movement. The present study indicates that the mixed crystals with x = 0.2 and 0.5 are not only promising nonlinear optical materials but also useful as low dielectric constant materials.

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