Self-Healing Audio System

Installed sound applications typically involve a large number of audio processors, amplifiers and speaker systems spread across the venue. They could be spatially distributed at the venue across different rack rooms and floors. These systems are commissioned and configured by sound engineers using software application(s). This is essentially a one-time activity, following which, the audio systems run independently. Detection of faults and reconfiguration of any audio device(s) that fail(s) is a time-consuming operation. This disruption in the audio system can affect the entire audio chain and affect the usability of the venue in question. In this paper, we provide an overview of an audio system that detects the replacement for any faulty audio device(s) in the network and re-purposes the same to restore the configuration to last working point.Comment: Accepted at IEEE sponsored International Conference on Computer Communication and Informatics,2016. It will be published in IEEE Xplore Digital library after paper presentatio

Domain wall dynamics in antiferromagnetically-coupled double-lattice systems

In ferromagnetic materials, the rich dynamics of magnetic domain walls (DWs) under magnetic field or current have been successfully described using the well-known q-{\phi} analytical model. We demonstrate here that this simple unidimensional model holds for multiple-sublattice materials such as ferrimagnetic alloys or synthetic antiferromagnets (SAF) by using effective parameters, and is in excellent agreement with double-lattice micromagnetic simulations. We obtain analytical laws for the DW velocity and internal precession angle as a function of net magnetisation for different driving forces (magnetic field, spin transfer and spin-orbit torques) and different propagation regimes in ferrimagnetic alloys and SAFs. The model predicts that several distinctive dynamical features occur near or at the magnetic and the angular compensation points when the net magnetization or the net angular momentum of the system vanishes, and we discuss the experimental observations that have been reported for some of them. Using a higher degree-of-freedom analytical model that accounts for inter-sublattice distortions, we give analytical expressions for these distortions that agree with the micromagnetic simulations. This model shows that the DW velocity and precession rate are independent of the strength of the inter-sublattice exchange coupling, and justifies the use of the simpler effective parameters model

An integrative approach towards prevention & management of psychological illnesses during COVID 19 crisis

Widespread outbreaks of infectious disease, such as COVID-19, are associated with psychological distress and symptoms of mental illness. To date (June 29th, 2020), over 10,021,401 confirmed cases and 499,913 deaths attributable to this disease have been reported. Ayurveda though being an ancient life science clearly mentions about such disease conditions. A detailed chapter on Janapadodhwansa in Charaka Samhita explains epidemic disease and its etiological factors. Adharma as the root cause of Janapadodhwansa. The current article is a narrative review of the existing literature on mental health symptoms and interventions relevant to the COVID-19 pandemic. Psychiatric and psychological problems that were present before the pandemic and the Patho-plastic effects of the pandemic on these problems; the responses to social isolation and lockdown; the psychological response to the diagnosis public responses to those with symptoms suggestive of COVID-19 infection, as well as the aftermath ofthe infection. Timely identification of high-risk groups especially those with prior mental health issues, are essential to prevent extreme events such as suicide and other impulsive behaviors. Acharya Charaka has described Chikitsa Siddhant to be followed during Janapadoudhwamsa; Karma Panchavidham, Rasayananamupyoga. Langhan, Langhan-Pachana and Doshavasechan. Harsha Prinananam - Cheerful mind best in bringing delightfulness. Charaka has also stated that the disease of a patient having Pravara-Sattva recovers quickly as compared to patients of Avara-Sattva. Also, body and mind follow and influences each other i.e. any kind of change in mental status results in both physiological as well as psychological variation from normalcy

Spin orbit torque induced asymmetric depinning of chiral Néel domain wall in Co/Ni heterostructures

In this letter, we report on distinct depinning of a chiral Néel domain wall (DW) driven by spin-orbit torque (SOT) in Co/Ni nanowires with symmetric potential barriers. In these structures, DW propagation was shown to be in the opposite direction to the electron flow as evidenced from current assisted DW depinning measurements. A transition from field dominated DW depinning to SOT dominated DW depinning was observed as the bias current was increased. For SOT dominated DW depinning, the Up-Down DW exhibits a larger depinning field as compared to the Down-Up DW. This is attributed to the interplay between the SOT and Dzyaloshinskii-Moriya interaction in the structure

Quantifying orbital Rashba effect via harmonic Hall torque measurements in transition-metal|Cu|Oxide structures

Spin-orbit interaction (SOI) plays a pivotal role in the charge-to-spin conversion mechanisms, notably the spin Hall effect involving spin-dependent deflection of conduction electrons and the interfacial spin Rashba-Edelstein effect. In recent developments, significant current-induced torques have been predicted and observed in material systems featuring interfaces with light elements \textit{i.e.} possessing a weak SOI. These findings challenge existing mechanisms and point to the potential involvement of the orbital counterpart of electrons, namely the orbital Hall and orbital Rashba effects. Here, we establish, in Pt|Co|Cu|AlOx stacking, the comparable strength between the orbital Rashba effect at the Cu|AlOx interface and the effective spin Hall effect in Pt|Co. Subsequently, we investigate the thickness dependence of an intermediate Pt layer in Co|Pt|Cu|CuOx, revealing the strong signature of the orbital Rashba effect at the Cu|CuOx interface besides the well-identified Pt intrinsic spin Hall effect. Leveraging such contribution from the orbital Rashba effect, we show a twofold enhancement in the effective torques on Co through harmonic Hall measurements. This result is corroborated by complementary spin Hall magneto-resistance and THz spectroscopy experiments. Our results unveil unexplored aspects of the electron's orbital degree of freedom, offering an alternative avenue for magnetization manipulation in spintronic devices with potential implications for energy-efficient and environmentally friendly technologies using abundant and light elements.Comment: 11 pages, 5 figure

Neuromorphic weighted sum with magnetic skyrmions

Integrating magnetic skyrmion properties into neuromorphic computing promises advancements in hardware efficiency and computational power. However, a scalable implementation of the weighted sum of neuron signals, a core operation in neural networks, has yet to be demonstrated. In this study, we exploit the non-volatile and particle-like characteristics of magnetic skyrmions, akin to synaptic vesicles and neurotransmitters, to perform this weighted sum operation in a compact, biologically-inspired manner. To this aim, skyrmions are electrically generated in numbers proportional to the input with an efficiency given by a non-volatile weight. These chiral particles are then directed using localized current injections to a location where their presence is quantified through non-perturbative electrical measurements. Our experimental demonstration, currently with two inputs, can be scaled to accommodate multiple inputs and outputs using a crossbar array design, potentially nearing the energy efficiency observed in biological systems.Comment: 12 pages, 5 figure

Driving skyrmions in flow regime in synthetic ferrimagnets

Despite significant advances in the last decade regarding the room temperature stabilization of skyrmions or their current induced dynamics, the impact of local material inhomogeneities still remains an important issue that impedes to reach the regime of steady state motion of these spin textures. Here, we study the spin-torque driven motion of skyrmions in synthetic ferrimagnetic multilayers with the aim of achieving high mobility and reduced skyrmion Hall effect. We consider Pt|Co|Tb multilayers of various thicknesses with antiferromagnetic coupling between the Co and Tb magnetization. The increase of Tb thickness in the multilayers allows to reduce the total magnetic moment and increases the spin-orbit torques allowing to reach velocities up to 400 m.s-1 for skyrmions with diameters of about 160 nm. We demonstrate that due to reduced skyrmion Hall effect, combined with the edge repulsion of the magnetic track making the skyrmions moving along the track without any transverse deflection. Further, by comparing the field-induced domain wall motion and current-induced skyrmion motion, we demonstrate that the skyrmions at the largest current densities present all the characteristics of a dynamical flow regime.Comment: 14 pages, 4 figure

Current-driven domain wall dynamics in coupled ferromagnetic structures

The manipulation of the magnetic moments in ferromagnetic (FM) layers via various spin torques has enabled the spintronics research community to encode the digital data in low-power, non-volatile memory and logic devices e.g. spin-transfer torque magnetic random-access memory (STT-MRAM). In this thesis, current-induced coupled domain wall (DW) dynamics are investigated in both in-plane and perpendicular magnetic anisotropy materials via experimental and micromagnetic simulations. The effect of DW stray field on DW dynamics in a neighbouring NiFe nanowire with in-plane magnetic anisotropy is studied using micromagnetic simulations. The DWs in the multi-nanowire systems are driven by passing spin-polarized currents to one of the nanowire. The phenomenon is made possible due to the magnetostatic coupling between the DWs. The coupling strength between the DWs in two nanowires strongly depends on the chirality of the DWs and the inter-wire spacing. This coupling-induced DW motion further shifts the Walker breakdown limit towards higher current densities. Current-induced magnetization manipulation in antiferromagnetically coupled thin films with perpendicular magnetic anisotropy is investigated experimentally. FM/Ru/FM synthetic antiferromagnetic (SAF) structures are sandwiched between heavy metals to generate the spin-currents via spin Hall effect (SHE) phenomenon. A qualitative method is proposed to determine the spin-orbit torque (SOT) effective fields. The SOT fields in the SAF structures are found to be a vector sum of the individual SOT fields of the two FM layers. The SOT fields were oriented in antiparallel direction to each other in the two FM layers and efficiently modulated by tuning the net areal magnetization of the SAF structure. Furthermore, the current-induced magnetization switching in the SAF structures was achieved with the assistance of RKKY coupling. The DWs in the SAF structures are driven by nanosecond long current pulses. The RKKY exchange torque on the SOT-driven antiferromagnetically coupled Néel DWs can move the Néel DWs with a velocity of ~ 300 m/s at a current density of 1.04×1012 A/m2. The interplay between the SOT and RKKY coupling and its effect on the DWs dynamics are explained via the micromagnetic simulations. In addition, the SAF magnetic memory devices are irradiated by high energy proton beams to investigate the effect of the radiation on the data. In our investigation, the SAF magnetic memory devices are found to be radiation hard and the DW memory devices are still able to perform continuous data writing and reading even after being irradiated by several high energy proton beams. The devices are annealed at different temperatures over a range of time spans in atmosphere and the thermal stability factor (Δ) is calculated for the data retention. The SAF DW memory devices are found to have Δ ≈ 33 at an elevated temperature of T =190' C.​Doctor of Philosophy (SPMS