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V. R. K. Murthy

Bio: V. R. K. Murthy is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Dielectric & Rietveld refinement. The author has an hindex of 27, co-authored 162 publications receiving 2595 citations. Previous affiliations of V. R. K. Murthy include VIT University & Indian Institute of Science.


Papers
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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

Journal ArticleDOI
TL;DR: In this paper, specific volume and ultrasonic velocity as a function of temperature are carried out in different natural oils and fats of plant origin and it is found that the mango kernel fat exhibits liquid crystal-like molecular order at T < 317 K. The variation of these parameters with temperature is also studied and the results are discussed critically.
Abstract: Investigations of specific volume and ultrasonic velocity as a function of temperature are carried out in different natural oils and fats of plant origin. From these studies it is found that the mango kernel fat exhibits liquid crystal-like molecular order at T < 317 K. Various ultrasonic parameters like adiabatic compressibility, molar sound velocity, molar compressibility, van der Waal's constant, and intermolecular free length are evaluated. The variation of these parameters with temperature is also studied and the results are discussed critically.

4 citations

Journal ArticleDOI
TL;DR: In this article, the authors synthesize magnetoelectric composites by sintering mixtures of Pb(Zr0.52Ti0.48O3, PZT and highly magnetostrictive piezomagnetic component Ni0.93Co0.05Fe1.95O4-δ, NCMF.
Abstract: Magnetoelectric composites have been synthesized by sintering mixtures of highly piezoelectric component Pb(Zr0.52Ti0.48)O3, PZT and highly magnetostrictive piezomagnetic component Ni0.93Co0.02Mn0.05Fe1.95O4-δ, NCMF. These composites with generic formula (1 - x)PZT + xNi0.93Co0.02Mn0.05Fe1.95O4-δ, where x varies as 0.1, 0.3 and 0.5 mole fractions, were prepared from the powders of the pure components by the conventional ceramic route. The presence of two phases in multiferroic was confirmed by XRD technique. The variation of dielectric constant and dissipation factor, as a function of frequency from 100 Hz to 1 MHz and in the temperature range of 30–500°C were studied. The piezoelectric d33 coefficient of these composites was also studied in these composites. The magnetoelectric (ME) output voltage was measured in terms of the dE/dH as a function of magnetic bias field. A high value of ME output (1200 mV/Oe · cm) was obtained in the composite containing 70% ferroelectric phase (PbZr0.52Ti0.48O3) and 30% ferrite phase (Ni0.93Co0.02Mn0.05Fe1.95O4-δ). These multiferroic particulate composites are used as sensors and transducers.

4 citations

Journal ArticleDOI
TL;DR: The dependence of the microwave dielectric properties of xBa 3 MgNb 2 O 9 −(1-x)Ba 2 InNbO 6 [x = 0.4, 0.6,0.8] on the structural parameters is investigated in this paper.

4 citations

01 Jul 2001
TL;DR: In this paper, a semi-empirical analysis of the dielectric properti es or the hydrogen bonded binary system of non-associated polar liquid methyl benzoate (ester) and rolar liquid ani line (primary am~) has been performed.
Abstract: Th dielectric properti es or the hydrogen bonded binary system of non-associated polar liquid methyl benzoate (ester) and rolar liquid ani line (primary am~) have been smttrectOn15OtiiPure and equ imolar binary mixtures of methyl benzoate and an iline in dilute so lutions of benzene. AM I semi -empiri ca l calcu lati ons are performed on various conformers of the hydrogen honded comrlex . The minimum cnergy conformer is then selected and ah initio geometry optimization is rcrrormeci with 6-3! g(d ) hasis set. Self-consistent reaction fie ld calculations have been performed on the resu ltant geometry to include solvent effects. The calculated dipole moment is compared with the experimental valoe.) I b V

4 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Proceedings Article
01 Jan 1999
TL;DR: In this paper, the authors describe photonic crystals as the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures, and the interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.
Abstract: The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

2,722 citations

01 Sep 1955
TL;DR: In this paper, the authors restrict their attention to the ferrites and a few other closely related materials, which are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present.
Abstract: In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

2,659 citations

Journal ArticleDOI
TL;DR: In this article, a 3d transition metal-doped ZnO films (n-type Zn1−xMxO) were formed on sapphire substrates using a pulsed-laser deposition technique, and their magnetic and electric properties were examined.
Abstract: 3d-transition-metal-doped ZnO films (n-type Zn1−xMxO (x=005–025): M=Co, Mn, Cr, Ni) are formed on sapphire substrates using a pulsed-laser deposition technique, and their magnetic and electric properties are examined The Co-doped ZnO films showed the maximum solubility limit Some of the Co-doped ZnO films exhibit ferromagnetic behaviors with the Curie temperature higher than room temperature The magnetic properties of Co-doped ZnO films depend on the concentration of Co ions and carriers

1,852 citations

Journal ArticleDOI
TL;DR: In this paper, a review focusing on promising candidate materials (such as GaN, GaP and ZnO) is presented, where the introduction of Mn into these and other materials under the right conditions is found to produce ferromagnetism near or above room temperature.
Abstract: Recent advances in the theory and experimental realization of ferromagnetic semiconductors give hope that a new generation of microelectronic devices based on the spin degree of freedom of the electron can be developed. This review focuses primarily on promising candidate materials (such as GaN, GaP and ZnO) in which there is already a technology base and a fairly good understanding of the basic electrical and optical properties. The introduction of Mn into these and other materials under the right conditions is found to produce ferromagnetism near or above room temperature. There are a number of other potential dopant ions that could be employed (such as Fe, Ni, Co, Cr) as suggested by theory [see, for example, Sato and Katayama-Yoshida, Jpn. J. Appl. Phys., Part 2 39, L555 (2000)]. Growth of these ferromagnetic materials by thin film techniques, such as molecular beam epitaxy or pulsed laser deposition, provides excellent control of the dopant concentration and the ability to grow single-phase layers. T...

968 citations