Multilayer Ferromagnetic Spintronic Devices for Neuromorphic Computing Applications

Spintronics has gone through substantial progress due to its applications in energy-efficient memory, logic and unconventional computing paradigms. Multilayer ferromagnetic thin films are extensively studied for understanding the domain wall and skyrmion dynamics. However, most of these studies are confined to the materials and domain wall/skyrmion physics. In this paper, we present the experimental and micromagnetic realization of a multilayer ferromagnetic spintronic device for neuromorphic computing applications. The device exhibits multilevel resistance states and the number of resistance states increases with lowering temperature. This is supported by the multilevel magnetization behavior observed in the micromagnetic simulations. Furthermore, the evolution of resistance states with spin-orbit torque is also explored in experiments and simulations. Using the multi-level resistance states of the device, we propose its applications as a synaptic device in hardware neural networks and study the linearity performance of the synaptic devices. The neural network based on these devices is trained and tested on the MNIST dataset using a supervised learning algorithm. The devices at the chip level achieve 90\% accuracy. Thus, proving its applications in neuromorphic computing. Furthermore, we lastly discuss the possible application of the device in cryogenic memory electronics for quantum computers

Large amplitude ion-acoustic solitons in warm negative ion plasmas with superthermal electrons

Large amplitude ion-acoustic solitons are investigated in a plasma consisting of warm adiabatic positive and negative-ions and hot superthermal electrons having kappa distributions. Using Pseudo-potential method an energy integral equation is derived for the system. The latter is analysed to examine the existence regions of the solitary waves. It is found that negative ion concentration (α), spectral index (k) and ionic temperature ratio (σ1 or σ2) significantly influence the characteristic of the solitons. Our numerical analysis shows that the system also supports rarefactive solitons for some selected set of plasma parameters. It is also found that large amplitude ion-acoustic compressive and rarefactive solitons exist simultaneously for the same values of plasma parameters. Further an increase in the superthermality (i.e. decreasing the value of spectral index k) leads to shrinking the existing domain of the large amplitude ion-acoustic solitons. The amplitude of the compressive/rarefactive solitons increases with the increase in negative ion concentration (α). Whereas, on increasing ionic temperature ratio (σ1 or σ2) the amplitude of the compressive/rarefactive soliton decreases. The effect of negative-ion concentration (α), temperature ratio of two ion species (σ1 and σ2), Mach number (M) and spectral index (k) on the characteristics of solitons are discussed in detail. The results of the present investigation may be helpful to understand the nonlinear ion-acoustic solitary waves in space plasma and laboratory plasmas, where two distinct groups of ions and non-Boltzmann distribution electrons are present

Ozone: A Potent Disinfectant for Application in Food Industry -An Overview

504-509With the emergence of new microbial strains like Listeria, virulent E. coli, assorted viruses and accumulation of toxic chemicals in environment increased attention has been given to the safe use of sanitizers, bleaching agents, pesticides, etc., in industrial processing. The food industry, in particular, is in search of disinfectants that are effective against pathogens and are safe to use in specific applications. Ozone (O3), is effective against majority of microorganisms tested and its applications in the food industry are related to decontamination of product surface and water treatment. Ozone has been used with success to inactivate contaminant micro flora on meat, fruits, vegetables, and dry foods. Excessive use of ozone, however, may cause oxidation of some ingredients on food surface. Additional research is needed to optimize its use in food applications. The paper reviews the various aspects of ozone as a disinfectant for different applications in food industry