J. Benet Charles

Growth and microhardness studies on NH4Sb3F10 single crystals

Abstract Ammonium fluoride NH 4 F and antimony triflouride SbF 3 from many stoichiometric compounds, such as NH 4 SbF 4 , (NH 4 ) 2 SbF 5 , NH 4 Sb 2 F 7 , (NH 4 ) 3 Sb 2 F 9 , NH 4 Sb 3 F 10 , etc. Since (NH 4 ) 2 SbF 5 exhibits superionic conductivity and undergoes phase transitions, an attempt has been made to grow other stoichiometric compounds of this group. In this report, we deal with the growth and microhardness studies of NH 4 Sb 3 F 10 single crystals. Crystals of size 60 × 25 × 35 mm 3 were grown in a period of two months. Microhardness studies have been carried out using a Vickers diamond pyramid indenter. To study the anisotropy of this material, specimens cut in different orientations such as (001), (010), (100), (101), (μ01) have been subject to microhardness studies. The results show strong anisotropy in the work-hardening coefficient for different orientations. This anisotropy is explained on the basis of a plastic deformation model.

X-ray and electrical characterization of NaSb2F7 single crystals

Abstract Single crystal X-ray analysis of NaSb2F7 have been carried out and cell parameters are determined. From thermal analysis the weight loss, thermal stability and decomposition temperatures have been determined. The d.c. electrical conductivity of NaSb2F7 at (100), (010) and (001) orientations have been carried out in the temperature range from 30 °C to 175 °C. Dielectric constant (ϵ′) and dielectric loss (tanδ) have been measured in the range from 0.1 KHz to 100 KHz and at temperatures-between 30 °C to 175 °C.

Crystal growth and electrical studies of NaSb3F10 crystals

Abstract Single crystals of NaSb3F10 have been grown from solution by a slow-evaporation technique at constant temperature (305 K). The grown crystals were confirmed by chemical and X-ray analyses. The electrical conductivity studies of NaSb3F10 have been carried out in the temperature range from 30 to 190°C. The dielectric constant (ϵ) and dielectric loss (tan δ) were determined as a function of frequency in the range from 100 Hz to 100 kHz and in the temperature range from 30 to 190°C. The values of ϵ11 and ϵ13 for NaSb3F10 at 100 kHz are about 14 and 19 respectively.