Dielectric and thermal studies on gel grown strontium tartrate pentahydrate crystals

Abstract

Results of dielectric and thermal studies on strontium tartrate pentahydrate crystals are described. The value of dielectric constant is shown to be independent of temperature till 360 K at all the frequencies (110-700 kHz) of the applied a.c. field. It increases abruptly achieving a peak value of 25⋅5 at 100 kHz; the peak value being strongly dependent on frequency. In the temperature range, 87 < T < 117°C, the value of ε′ falls suggesting a transition at around 100°C or so. The dielectric constant, ε′, of the material is shown to be frequency dependent but temperature independent in the pre-or post-T c range 87 < T < 117°C, suggesting that the contribution towards polarization may be due to ionic or space charge polarization which gets eliminated at higher frequencies. The ferroelectric transition is supported by the results of thermoanalytical studies. It is explained that crystallographic change due to polymorphic phase transition may be occurring in the material, besides the change due to loss of water molecules, which leads to the dielectric anomaly at around 100°C. Coats-Redfern approximation method is applied for obtaining non-isothermal kinetic parameters leading to calculation of activation energies corresponding to three decomposition stages of material in the temperature ranging from 379-1113 K.

Structural Refinements and Thermal Properties of L(+)-Tartaric, D(–)-Tartaric, and Monohydrate Racemic Tartaric Acid

“…Many tartrate compounds are formed by the reaction of tartaric acid with various positive ions and are used in numerous industrial applications for transducers and in linear and non-linear mechanical devices due to their excellent dielectric, ferroelectric, piezoelectric, and nonlinear optical properties (Abdel-Kader et al, 1991;Desai & Patel, 1988;Firdous et al, 2010;Torres et al, 2002). Several types of tartaric acid crystals, such as potassium hydrogen tartrate, KC 4 H 5 O 6 , and calcium tartrate, CaC 4 H 4 O 6 , develop naturally in bottled wine and are the major cause of wine's natural and harmless sediment (Boese & Heinemann, 1993;Buschmann & Luger, 1985;Derewenda, 2008;Hawthorne et al, 1982).…”

Growth, Characterization and Dielectric Property Studies of Zinc Succinate Crystals Grown in Silica Gel Medium

“…Also in fig.9 the loss tangent is plotted against frequency. The peaks observed in this plot indicate the presence of relaxing dipoles in the sample [20,21] …”

Growth and Physical Properties of Pure and Manganese Doped Strontium Tartrate Trihydrate Single Crystals

“…The three different stages identified along with the corresponding temperature ranges and mass losses are provided in Table 3. The first stage corresponds to the removal of water molecules (dehydration process) [13]. The second stage corresponds to the formation of strontium oxalate (SrC 2 O 4 ) (decomposition process).…”

“…The presence of two hydroxyl as well as two carbonyl groups in tartaric acid permits the ready incorporation of monovalent, divalent or trivalent metal ions [1]. Mainly tartrate crystals possess application as dielectric, ferroelectric and piezoelectric materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. They are used in the fabrication of nonlinear optical (NLO) devices such as crystal oscillators and resonators based on their optical second harmonic generation (SHG), optical transmission characteristics, and controlled laser emission [2].…”

“…Manganese tartrate crystals are used in chemical temperature indicators [3]. Among the several tartrate compounds, strontium tartrate has received greater attention on account of its ferroelectric, nonlinear optical and spectral characteristics [1,2,[7][8][9][10][11]13,14].…”