Mahesh Kumar
Articles written in Bulletin of Materials Science
Volume 21 Issue 3 June 1998 pp 251-255
An experimental setup for dynamic measurement of magnetoelectric effect
M Mahesh Kumar A Srinivas S V Suryanarayana G S Kumar T Bhimasankaram
An experimental setup is developed for the measurement of dynamic magnetoelectric effect (ME) in polycrystalline materials, using a time varying DC magnetic field on which an AC magnetic field is superimposed. The experimental data on ME on Bi5FeTi3O15 and a solid solution of (90%)BiFeO3-(10%)BaTiO3 are obtained using this setup. The linear and higher order ME coefficients can be evaluated from the output voltage. The temperature variation of ME data gives additional information corroborating with the data on magnetization.
Volume 33 Issue 3 June 2010 pp 221-226 Thin Films and Nanomatter
Mahesh Kumar T N Bhat M K Rajpalke B Roul P Misra L M Kukreja Neeraj Sinha A T Kalghatgi S B Krupanidhi
Nanosized hexagonal InN flower-like structures were fabricated by droplet epitaxy on GaN/Si(111) and GaN flower-like nanostructure fabricated directly on Si(111) substrate using radio frequency plasma-assisted molecular beam epitaxy. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study the crystallinity and morphology of the nanostructures. Moreover, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) were used to investigate the chemical compositions and optical properties of nano-flowers, respectively. Activation energy of free exciton transitions in GaN nano-flowers was derived to be ∼ 28.5 meV from the temperature dependent PL studies. The formation process of nanoflowers is investigated and a qualitative mechanism is proposed.
Volume 43 All articles Published: 20 August 2020 Article ID 0234
Gallium nitride nanocrystal formation in Si$_3$N$_4$ matrix by ion synthesis
MANOJ KUMAR RAJBHAR SARAVANAN RAJAMANI S K SINGH SERGEY SURODIN DMITRY NIKOLICHEV RUSLAN KRYUKOV DMITRY KOROLEV ALYONA NIKOLSKAYA ALEXEY BELOV ALEXEY NEZHDANOV ALEXEY MIKHAYLOV DAVID TETELBAUM MAHESH KUMAR
Synthesis of nanoparticles in insulators attracts tremendous attention due to their unique electrical and optical properties. Here, the gallium (Ga) and gallium nitride (GaN) nanoclusters have been synthesized in the silicon nitridematrix by sequential ion implantation (gallium and nitrogen ions) followed by either furnace annealing (FA) or rapid thermal annealing (RTA). The presence of Ga and GaN nanoclusters has been confirmed by Fourier-transform infrared,Raman and X-ray photoelectron spectroscopy. Thereafter, the effect of RTA and FA on the conduction of charge carriers has been studied for the fabricated devices. It is found from the current–voltage measurements that the carrier transport is controlled by the space charge limited current conduction mechanism, and the observed values of parameter $m$ (trap density and the distribution of localized state) for the FA and RTA devices are $\sim$2 and $\sim$4.1, respectively. This reveals that more defects are formed in the RTA device and that FA provides better performance than RTA from the viewpoint ofopto- and nano-electronic applications.
Volume 45, 2022
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Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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