Showing papers by "V. R. K. Murthy published in 1997"
TL;DR: In this article, the temperature coefficient of dielectric constant follows the same trend as in some complex perovskite materials with respect to the tolerance factor, which is quite opposite to what is observed in some other perovsite materials.
Abstract: Microwave dielectric properties of some simple alkaline earth perovskite compounds were studied with respect to the variation in the tolerance factor. It was found in the present study that the variation in dielectric constant (e), Qf o product and the temperature coefficient of polarizability with tolerance factor is quite opposite to what is observed in some complex perovskite materials. It was also observed that the temperature coefficient of dielectric constant follows the same trend as in some complex perovskite materials with respect to the tolerance factor.
51 citations
TL;DR: In this article, a new theoretical method of evaluating polarizabilities of liquid crystals is presented and applied to the liquid crystalline compounds, namely n-alkyl-p-(4-ethoxy benzylidene amino)-α-methyl cinnamates, which exhibit smectic A and nematic phases.
Abstract: A new theoretical method of evaluating polarizabilities of liquid crystals is presented and applied to the liquid crystalline compounds, namely n-alkyl-p-(4-ethoxy benzylidene amino)-α-methyl cinnamates, which exhibit smectic A and nematic phases. In the present method, vibrational frequencies are used to evaluate force constants, mean amplitude of vibration and hence bond polarizabilities. From mean polarizabilities, polarizability anisotropies and mean diamagnetic susceptibilities are also estimated. A close agreement is found between the values estimated from the present molecular vibration method and the reported data, which confirms the applicability of this method to the liquid crystals exhibiting smectic A and nematic phases. In addition, the variation of the order parameter with temperature is also studied. PACS numbers: 61.30.—v
14 citations
TL;DR: In this article, the binding energy of graphite ferric chloride intercalation compounds (FeCl3-GICs) has been investigated using X-ray photoelectron spectroscopic (XPS) analysis.
12 citations
TL;DR: In this paper, the dielectric properties of a D resonator with x = 0.7 were studied by adjusting the Nd/Sm ratio, which gave high ǫ r, high Q and low τ f.
Abstract: Microwave dielectric properties of dielectric resonators (BaNd2(1 − x)Sm2xTi5O14) with high dielectric constant (ɛr), low loss (high Q) and low temperature coefficient of resonant frequency (τf) have been studied by adjusting the Nd/Sm ratio. The composition with x = 0.7 gives high ɛr, high Q and low τf which is highly suitable for dielectric resonators (DR).
11 citations
TL;DR: In this paper, the effect of magnetic field on the temperature dependence of internal friction has been studied in the case of Mn-Zn spinel ferrites in the manganese-rich region, developed for their use as TV deflection coil yokes.
Abstract: Internal friction Q -1 of Mn-Zn spinel ferrites in the manganese-rich region, developed for their use as TV deflection coil yokes, has been studied in the temperature range from 300 to 630 K. Two distinct stress induced relaxation peaks have been observed in the internal friction versus temperature curves. The magnetic transition has been observed to change with the concentration of zinc. The effect of magnetic field on the temperature dependence of internal friction has also been studied. The increase of zinc content in this system drastically alters the acoustic relaxations. The results are discussed in the light of Jahn-Teller distortion and cationic exchange between octahedral and tetrahedral sublattices and clustering of octahedral Mn 3+ ions.
6 citations
TL;DR: In this paper, mean molecular polarizabilities, polarizability anisotropies and order parameters are evaluated in members of three homologous series, using two theoretical models.
Abstract: Mean Molecular polarizabilities, polarizability anisotropies and order parameters are evaluated in members of three homologous series, using two theoretical models. The variation of polarizabilities and their anisotropies with number of carbon atoms in the alkyl chain is studied. The temperature dependence of order parameter is also presented. The results are compared with the reported values and the merits of the different models are discussed.
4 citations
TL;DR: In this article, the elastic behavior of polycrystalline Mn-Zn ferrite system in Mn-rich region has been studied in the temperature range 300-650 K at saturation magnetic fields using the resonant piezoelectric oscillator technique.
3 citations
TL;DR: In this article, the X-band quality factor measurements for pure and mixed stages of graphite ferric chloride intercalation compounds have been carried out at X band microwave frequency of 9.1582 GHz.
Abstract: Microwave quality factor measurements for pure and mixed stages of graphite ferric chloride intercalation compounds have been carried out at X-band microwave frequency of 9.1582 GHz. The change in quality factor and hence the loss confirms the metallic nature of the graphite ferric chloride intercalation compounds that were studied.