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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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Journal ArticleDOI
TL;DR: In this article, the authors measured the dielectric parameters of lithium-zinc ferrites with chemical formula Li0.5−x/2Fe2 and showed an increase in dielectrics with temperature.
Abstract: Microwave dielectric parameters are measured for lithium‐zinc ferrites with chemical formula Li0.5−x/2Fe2.5−x/2ZnxO4 (x=0.0, 0.1, 0.3, 0.5, 0.6). All the samples except x=0.5, show an increase in the dielectric loss with temperature. A relaxation‐type mechanism is observed for x=0.5. The results are compared with the low‐frequency dielectric constant and loss.

15 citations

Journal ArticleDOI
TL;DR: The molecular interaction between the polar systems of propan-1-ol and propionaldehyde for various mole fractions at different temperatures were studied by determining the frequency dependent complex dielectric permittivity by using the open-ended coaxial probe technique method.

15 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the tilting of octahedra on polar phonon modes of lattice vibration was investigated, which contributes a major part to the dielectric polarization in the crystal.
Abstract: The aim of this work is to understand the effect of the tilting of octahedra on polar phonon modes of lattice vibration, which contributes a major part to the dielectric polarization in the crystal. The tolerance factor, which is a measure of the packing of ions in the perovskite unit cell, determines the tilting of oxygen octahedra in the perovskite materials. In this work we have discussed the variation of polar phonon frequencies with respect to the tolerance factor in the composition (Ba(1−x)Srx)(Zn1/3Ta2/3)O3 with x=0.0,0.3,0.5,0.7,1.0. The dielectric properties measured at the microwave frequency range are also highlighted to support the ideas proposed in this paper.

15 citations

Journal ArticleDOI
TL;DR: In this article, the dielectric behavior of polar liquids such as propan-1-ol, propionaldehyde and their equimolar binary mixture in non-polar solvent benzene is studied in the microwave frequency range using the cavity perturbation technique at 6.218 GHz (J band), 9.880 GHz (X band), 16.331 GHz (P band) and 24.951 GHz (K band).
Abstract: The dielectric behaviour of polar liquids such as propan-1-ol, propionaldehyde and their equimolar binary mixture in non-polar solvent benzene is studied in the microwave frequency range using the cavity perturbation technique at 6.218 GHz (J band), 9.880 GHz (X band), 16.331 GHz (P band) and 24.951 GHz (K band). Ab initio geometry optimization is performed in the 6-31G (d) basis set using the Gaussian 94W program for both pure and binary systems of propan-1-ol and propionaldehyde. Dipole moments of the binary mixtures are calculated from the dielectric data using Higasi's method and compared with the ab initio results. Conformational analysis of the formation of hydrogen bond between the propan-1-ol and propionaldehyde is supported by the FT-IR spectra. The average relaxation times are calculated from their respective Cole–Cole plots.

15 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