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Institution

Solid State Physics Laboratory

FacilityDelhi, India
About: Solid State Physics Laboratory is a facility organization based out in Delhi, India. It is known for research contribution in the topics: Quantum dot & Dielectric. The organization has 1754 authors who have published 2597 publications receiving 50601 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the growth of carbon-substituted magnesium diboride is reported and the structural, transport, and magnetization data are presented, and the superconducting transition temperature decreases monotonically with increasing carbon content in the full investigated range of substitution.
Abstract: The growth of carbon-substituted magnesium diboride $\mathrm{Mg}{({\mathrm{B}}_{1\ensuremath{-}x}{\mathrm{C}}_{x})}_{2}$ single crystals with $0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.15$ is reported, and the structural, transport, and magnetization data are presented. The superconducting transition temperature decreases monotonically with increasing carbon content in the full investigated range of substitution. By adjusting the nominal composition, ${T}_{c}$ of substituted crystals can be tuned in a wide temperature range between 10 and 39 K. Simultaneous introduction of disorder by carbon substitution and significant increase of the upper critical field ${H}_{c2}$ is observed. Comparing with the nonsubstituted compound, ${H}_{c2}$ at 15 K for $x=0.05$ is enhanced by more than a factor of 2 for $H$ oriented both perpendicular and parallel to the $ab$ plane. This enhancement is accompanied by a reduction of the ${H}_{c2}$-anisotropy coefficient $\ensuremath{\gamma}$ from 4.5 (for the nonsubstituted compound) to 3.4 and 2.8 for the crystals with $x=0.05$ and 0.095, respectively. At temperatures below 10 K, the single crystal with larger carbon content shows ${H}_{c2}$ (defined at zero resistance) higher than 7 and 24 T for $H$ oriented perpendicular and parallel to the $ab$ plane, respectively. Observed increase of ${H}_{c2}$ cannot be explained by the change in the coherence length due to the disorder-induced decrease of the mean free path only.

225 citations

Journal ArticleDOI
TL;DR: In this article, temperature dependence of resistivity, dielectric constant and Dielectric loss have been investigated for four different compositions of nickel-zinc ferrites, Nii_IZnIFe2O4 (x = 0.2, 0.5 and 0.6), prepared by the citrate precursor technique, and the variations in activation energy with composition and sintering temperature were explained on the basis of the site occupancy in ferrites and the atomic radii of the constituent metal ions.
Abstract: Temperature dependence of resistivity, dielectric constant and dielectric loss have been investigated for four different compositions of nickel-zinc ferrites, Nii_IZnIFe2O4 (x = 0.2, 0.35, 0.5 and 0.6), prepared by the citrate precursor technique. Activation energies calculated from the resistivity versus temperature curves for the compositions sintered at 1200 °C and 1300 °C range from 0.55 eV to 0.73 eV. Samples sintered at 1200 °C exhibit higher activation energies and low dielectric losses compared to those sintered at 1300 °C. Samples of the composition with x = 0.6 show low dielectric losses up to a measurement temperature of around 200 °C at higher frequencies as compared to samples of other compositions. The variations in activation energy with composition and sintering temperature have been explained on the basis of the site occupancy in ferrites and the atomic radii of the constituent metal ions.

225 citations

Journal ArticleDOI
03 Dec 1998-Nature
TL;DR: In this paper, the authors reported the observation of multiple temperature-induced magnetization reversals in YVO3 and proposed a possible mechanism involving a change in orbital ordering which may be generic to a broad class of transition metal oxides.
Abstract: The total energy of a magnet in a magnetic field is lowest when the magnetic moment is aligned parallel to the magnetic field. Once aligned, the magnetic moment can be reversed by applying a sufficiently large field in the opposite direction. These properties form the basis of most magnetic recording and storage devices. But the phenomenon of magnetization reversal in response to a change in temperature (in a small magnetic field) is rarer. This effect occurs in some ferrimagnetic materials consisting of two or more types of antiferromagnetically ordered magnetic ions1, and forms the operational basis of ferrimagnetic insulators. Here we report the observation of multiple temperature-induced magnetization reversals in YVO3. The net magnetic moment is caused by a tilting of the antiferromagnetically aligned moments of (crystallographically identical) V3+ ions, due to orthorhombic distortion in the crystal structure. We observe an abrupt switching at 77 K associated with a first-order structural phase transition, and a gradual reversal at ∼95 K without an accompanying structural change. The magnetization always reverses if the crystal is cooled or warmed through these two temperatures in modest fields. We propose a possible mechanism involving a change in orbital ordering which may be generic to a broad class of transition metal oxides.

225 citations

Journal ArticleDOI
TL;DR: In this paper, linear polarized x-ray-absorption spectroscopy was used to measure the temperature and thickness dependence of magnetic moments in NiO thin films, and both the long-range order and the nearest-neighbor spin-spin correlations can be revealed.
Abstract: We show that linear polarized x-ray-absorption spectroscopy can be used to measure the temperature and thickness dependence of magnetic moments in NiO thin films. We demonstrate that both the long-range order and the nearest-neighbor spin-spin correlations can be revealed. NiO (100) films with thicknesses of 5, 10, and 20 monolayers epitaxially grown on MgO (100) are studied. The N\'eel temperature is found to be strongly reduced from the bulk value even for the 20 monolayer film.

224 citations

Journal ArticleDOI
TL;DR: In this paper, spatially resolved Raman images of the G and 2D lines of single-layer graphene flakes were used to identify the position of the 2D line as a function of charging up to ∣n∣≈4×1012cm−2.
Abstract: We present spatially resolved Raman images of the G and 2D lines of single-layer graphene flakes. The spatial fluctuations of G and 2D lines are correlated and are thus shown to be affiliated with local doping domains. We investigate the position of the 2D line—the most significant Raman peak to identify single-layer graphene—as a function of charging up to ∣n∣≈4×1012cm−2. Contrary to the G line which exhibits a strong and symmetric stiffening with respect to electron and hole doping, the 2D line shows a weak and slightly asymmetric stiffening for low doping. Additionally, the linewidth of the 2D line is, in contrast to the G line, doping independent making this quantity a reliable measure for identifying single-layer graphene.

224 citations


Authors

Showing all 1757 results

NameH-indexPapersCitations
Alain Dufresne11135845904
Yang Ren7988026341
Klaus Ensslin7063821385
Werner Wegscheider6993321984
Takashi Takahashi6542414234
Liu Hao Tjeng6432213752
Nicholas E. Geacintov6345315636
Manfred Sigrist6146818362
Thomas Ihn6147514159
Takafumi Sato5926311032
Christoph Stampfer5931514422
Christian Colliex5828914618
Takashi Mizokawa5740011697
Eberhard Bodenschatz5737413208
Bertram Batlogg551909459
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
202210
202174
202087
201992
201878