Department of Physics

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

Using all atom molecular dynamics and trajectory-extending kinetic Monte Carlo simulations, we study the influence of Al2O3 nanoparticles on the transport properties of ions in polymer electrolytes composed of poly(ethylene oxide) (PEO) melt solvated with LiBF4 salt. We observe that the mobility of Li+ cations and BF4- anions and the overall conductivity decrease upon addition of nanoparticles. Our results suggest that the nanoparticles slow the dynamics of polymer segments near their surfaces. Moreover, the preferential interactions of the ions with the nanoparticles are seen to lead to an enhancement of ion concentration near the particle surfaces and a further reduction in the polymer mobilities near the surface. Together, these effects are seen to increase the residence times of Li+ cations near the polymer backbone in the vicinity of the nanoparticles and reduce the overall mobility and conductivity of the electrolyte. Overall, our simulation results suggest that both the nanoparticle-induced changes in polymer dynamical properties and the interactions between the nanoparticles and ions influence the conductivity of the electrolyte. © 2015 American Chemical Society.

World University root node

Macromolecules

Effect of nanoparticles on ion transport in polymer electrolytes

Room-temperature photocurrent measurements in two-dimensional (2D) inorganic-organic perovskite devices reveal that excitons strongly contribute to the photocurrents despite possessing binding energies over 10 times larger than the thermal energies. The p-type (C6H9C2H4NH3)2PbI4 liberates photocarriers at metallic Schottky aluminum contacts, but incorporating electron- and hole-transport layers enhances the extracted photocurrents by 100-fold. A further 10-fold gain is found when TiO2 nanoparticles are directly integrated into the perovskite layers, although the 2D exciton semiconducting layers are not significantly disrupted. These results show that strong excitonic materials may be useful as photovoltaic materials despite high exciton binding energies and suggest mechanisms to better understand the photovoltaic properties of the related three-dimensional perovskites. © 2015 American Chemical Society.

Fulltext

ACS Applied Materials and Interfaces

Strong Photocurrent from Two-Dimensional Excitons in Solution-Processed Stacked Perovskite Semiconductor Sheets

The magnetars are believed to be highly magnetized neutron stars having surface magnetic field 1014 − 1015 G. It is believed that at the center, the magnetic field may be higher than that at the surface. We study the effect of the magnetic field on the neutron star matter. We model the nuclear matter with the relativistic mean field approach considering the possibility of appearance of hyperons at higher density. We find that the effect of magnetic field on the matter of neutron stars and hence on the mass-radius relation is important, when the central magnetic field is atleast of the order of 1017 G. Very importantly, the effect of strong magnetic field reveals anisotropy to the system. Moreover, if the central field approaches 1019 G, then the matter becomes unstable which limits the maximum magnetic field at the center of magnetars. © 2015, World Scientific. All rights reserved.

The 13th Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proceedings of the MG13 Meeting on General Relativity, 2012

Constraining the central magnetic field of magnetars

We construct equilibrium models of compact stars using a realistic equation of state and obtain the density range occupied by the proton superconductor in strong B-fields. We do so by combining the density profiles of our models with microscopic calculations of proton pairing gaps and the critical unpairing field Hc2 above which the proton type-II superconductivity is destroyed. We find that magnetars with interior homogeneous field within the range 0.1 ≤ B16 ≤ 2, where B16 = B/1016 G, are partially superconducting, whereas those with B16 > 2 are void of superconductivity. We briefly discuss the neutrino emissivity and superfluid dynamics of magnetars in the light of their (non)-superconductivity. © 2015, Pleiades Publishing, Ltd.

Physics of Particles and Nuclei

Upper critical field and (non)-superconductivity of magnetars

Molecular machines (MM, Badjic, 2004; Collier, 2000; Jian & Tour, 2003; Koumura & Ferringa, 1999; Ding & Seeman, 2006) may resolve three distinct bottlenecks of scientific advancement (Bandyopadhyay, Fujita, Pati, 2008). Nanofactories (Phoenix, 2003) composed of MM may produce atomically perfect products spending negligible amount of energy (Hess, 2004) thus alleviating the energy crisis. Computers made by MM operating thousands of bits at a time may match biological processors mimicking creativity and intelligence (Hall, 2007), thus far considered as the prerogative of nature. State-of-the-art brain surgeries are not yet fatal-less, MMs guided by a nano-brain may execute perfect bloodless surgery (Freitas, 2005). Even though all three bottlenecks converge to a single necessity of nano-brain, futurists and molecular engineers have remained silent on this issue. Our recent invention of 16 bit parallel processor is a first step in this direction (Bandyopadhyay, 2008). However, the device operates inside ultra-high vacuum chamber. For practical application, one needs to design a 3 D standalone architecture. Here, we identify the minimum nano-brain functions for practical applications and try to increase the size from 2 nm to 20 μm. To realize this, three major changes are made. First, central control unit (CCU) and external execution units (EU) are modified so that they process information independently, second, CCU instructs EU the basic rules of information processing; third, once rules are set CCU does not hinder EU-computation. The basic design of the proposed nano-brain is a dendrimer (Hawker, 2005; Galliot, 1997; Devadoss, 2001; Quintana, 2002; Peer, 2007), with a control unit at its core and a molecular cellular neural network (m-CNN, Rosca, 1993; Chua, 2005) or Cellular Automata (CA, Wolfram, 1983) on its outer surface (EU). Each CNN/CA cell mimics the functionality of neurons by processing multiple bits reversibly (Rozenberg, 2004; Li, 2004; Bandyopadhyay, 2004). We have designed a megamer (Tomalia, 2005) consisting of dendrimer (~10 nm) as its unit CNN cell for building the giant 100 billion neuron based nano brain architecture. An important spontaneous control from 10 nm to 20 μm is achieved by an unique potential distribution following r=a sin kθ, where r is the co-ordinate of doped neuron cluster, k is the branch number, θ is the angle of deviation and a is a constant typical of the megamer architecture. © 2013, IGI Global.

Nanotechnology: Concepts, Methodologies, Tools, and Applications

An advanced architecture of a massive parallel processing nano brain operating 100 billion molecular neurons simultaneously

Co66Fe2Si13B15Cr4 based amorphous microwire was developed at the laboratory using in-water quenching apparatus. The field sensitivity of the wire was enhanced when coated with ferrofluids. The presence of coating also decreased the frequency of the magnetising field 5MHz to 1MHz at which the maximum GMI ratio observed. © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.

Physics Procedia

Giant magnetoimpedance (GMI) effect and field sensitivity of ferrofluid coated Co66Fe2Si13B15Cr4 soft magnetic amorphous microwire

The failure mechanism of two economizer tubes of a fossil fuelled 260. MW power plant has been investigated through the magnetic Barkhausen emission (MBE) technique along with the conventional and established materials characterization and evaluation techniques (like microstructures, mechanical properties and X-ray diffraction). The longer service exposer period results in the breaking of ferrite-pearlite structure and spheroidization lamellar cementite in ferrite matrix, associating with high magnetic r.m.s. voltage for former structure. The failure mechanism was governed by the cold end corrosion process with the presence of sulfates, and the subsequent erosion through hard quartz particles leads to a localized thinning of outer surface. Accordingly, the hoop stress was operative in tube walls and failed through fish-mouth opening. The MBE r.m.s. voltage response and pulse height distribution throw light on microstructural changes with duration of service exposure as well as leaked and non-leaked regions of economizer tubes. © 2014 Elsevier Ltd.

Engineering Failure Analysis

Damage evaluation of fossil fuelled power plant boiler tubes through magnetic Barkhausen technique

The butt joint of two sight tubes of modified 9Cr-1Mo steel is welded by TIG technique. Subsequently, the post-weld heat treatment (PWHT) of the tubes has been carried out at 650, 700 and 750°C temperatures for 3h. Magnetic Barkhausen emission (MBE) measurements are performed in fusion zone, heat affected zone (HAZ) and base metal region of as-welded and all the post-weld heat treated samples. In each weldment, the variation of the MBE signal emanated from fusion zone, HAZ and base metal has been examined. It is found that the RMS voltage of MBE signal increases with PWHT temperature. The conversion of retained austenite to alpha ferrite during PWHT makes the fusion region as a softer zone in the weldment. The variation of magnetic parameters with different PWHT is correlated with hardness and microstructures. This study can be used as an effective tool in evaluation of PWHT parameters in modified 9Cr-1Mo weld joint. © 2014 Elsevier Ltd.

International Journal of Pressure Vessels and Piping

Evaluation of post-weld heat treatment behavior in modified 9Cr-1Mo steel weldment by magnetic Barkhausen emission

The alloys Co64-xNi36Alx(at%, X=23,24,26 and 28) prepared through melt spinning technique revealed β- and γ-phase structure at room temperature. A monotonous increase in β-phase and simultaneous decrease in γ-phase has been observed with increasing Al content. The synergistic competition between β- and γ-phase influence β(B2)→L10 martensitic transformation. Therefore transformation broadening has been observed with Al content. Consequently, martensitic transformation temperature decreases and austenite transformation temperature increases. The γ-rich alloys showed magnetically soft phase, with high initial susceptibility and enhanced saturation magnetization. These alloys also revealed large magneto-strain values which are also supported by micro-structural morphology. © 2014 Elsevier B.V.

Journal of Magnetism and Magnetic Materials

Effect of Al incorporation for Co on the gamma-beta phase boundary of rapidly solidified CoNiAl ferromagnetic shape memory alloys

In a coded self-assembly, a simple code is written in the molecule, which self-assembles the molecules into a fractal like structure, which acts as a seed for the next step. As the molecule turns into a complex seed, the code transforms into another form and several seeds self-assemble into another structure, which acts as a seed for the next step. Until now, this technology was considered as a prerogative of nature. Here, a dendritic network is used to write a basic code by synthetically attaching 32 molecular rotors and doping two controller molecules in its cavity. The code live, which is an energy transmission path in the molecule, is imaged. When the energy transmission path or code is triggered, a series of products generate one after another spontaneously. Two examples are: i) dendritic seed (5-6 nm)→paired nanowire (≈12 nm)→nanowire (≈200 nm)→microwire (500 nm)→wire like rod (1-2 μm)→jelly→rectangular sheet (5 μm). ii) dendritic seed→nano-sphere (20 nm)→micro-sphere (500 nm)→large balls(1 μm)→oval shape rod (5-10 μm)→Y, L or T shaped rod assembly. The energy level interactions are tracked using spectroscopy how exactly a directed energy transfer code generates multi-step synthesis from nano to the visible scale. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.