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Evolution of structural and magnetic properties in a nickel/chromium (Ni/Cr) multilayer, as a function of different annealing temperatures was investigated. The Ni/Cr multilayer of nominal structure [Cr (50 Å)/Ni (50 Å)]×10/Cr (30 Å) was grown on a Si substrate by radio frequency ion beam sputtering at room temperature. X-ray diffraction, X-ray reflectometry, atomic force microscopy and crossectional scanning electron microscopy were employed for the complete structural characterization of the multilayer whereas superconducting quantum interference device vibration sample magnetometer was used for the bulk magnetisation study. The effect of in-situ and ex-situ annealing on overall structural property of the multilayer also reported in present work. From in-situ X-ray reflectometry (50–400 °C), 300 °C was detected as the optimum temperature for improved structural properties of the Ni/Cr multilayer. Initiation of alloying in the multilayer sample was noticed at 350 °C. The multilayer found to exhibit polycrystalline nature observed by X-ray diffraction. Total thickness of the multilayer system was confirmed by crossectional scanning electron microscopy and in well agreement with X-ray reflectivity results. The Ni/Cr sample found to exhibit soft ferromagnetic behaviour after annealing at 300 °C and 400 °C. However the net magnetic moment reduced upon annealing at higher temperature (400 °C).

In the pristine as well as the doped BiFeO3 samples, ferroelectric domains show switching behavior. The regions marked by yellow color loops show either 71° or 109°-domains, whereas those marked by white loops are 180°-domains.

g-C3N4/Ca2Fe2O5 heterostructures were successfully prepared by incorporating g-C3N4 into Ca2Fe2O5 (CFO). As prepared g-C3N4/CFO heterostructures were initially utilized to photodegrade organic effluent Methylene blue (MB) for optimization of photodegradation performance. 50% g-C3N4 content in CFO composition showed an enhanced photodegradation efficiency (~ 96%) over g-C3N4 (48.15%) and CFO (81.9%) due to mitigation of recombination of photogenerated charge carriers by Type-II heterojunction. The optimized composition of heterostructure was further tested for degradation of Bisphenol-A (BPA) under direct sunlight, exhibiting enhanced photodegradation efficiency of about 63.1% over g-C3N4 (17%) and CFO (45.1%). The photoelectrochemical studies at various potentials with and without light illumination showed significant improvement in photocurrent response for g-C3N4/Ca2Fe2O5 heterostructures (~ 1.9 mA) over CFO (~ 67.4 μA). These studies revealed efficient solar energy harvesting ability of g-C3N4/Ca2Fe2O5 heterostructures to be utilized for organic effluent treatment.

Quantum fluctuations enhanced by frustration and subtle interplay between competing degrees of freedom offer an ideal ground to realize novel states with fractional quantum numbers in quantum materials that defy standard theoretical paradigms. Quantum spin liquid (QSL) is a highly entangled state wherein frustration induced strong quantum fluctuations preclude symmetry breaking phase transitions down to zero temperature without any order parameter. Experimental realizations of QSL in quantum materials with spin dimensionality greater than one is very rare. Here, we present our thermodynamic, nuclear magnetic resonance, muon spin relaxation and inelastic neutron scattering studies of a new rare-earth hyperkagome compound Li3Yb3Te2O12 in which Yb3+ ions constitute a three dimensional spin-lattice without any detectable disorder. Our comprehensive experiments evince neither signature of magnetic ordering nor spin freezing down to 38 mK that suggest the realization of dynamic liquid-like ground state in this antiferromagnet. The ground state of this material is interpreted by a low energy Jeff = 1/2 degrees of freedom with short range spin correlations. The present results demonstrate a viable basis to explore spin-orbit driven enigmatic correlated quantum states in a new class of rare-earth based three dimensional frustrated magnets that may open new avenues in theoretical and experimental search for spin liquids.

We investigated the structural and optical properties of nanoparticle-assisted pulsed laser-deposited ZnO microrods and Au-coated ZnO microrods grown on Si substrate. Our present study indicates that Au-coated ZnO microrods exhibit whispering gallery modes (WGM) in the near band edge region with significant splitting into two branches. Moreover, the WGMs exhibited blue shift with decrease in rod size. We found that the modes are well split in Au coated ZnO rods when compared with as-grown rods, resulted from the plasmon enhancement of WGM modes. We also found that the Au-coated ZnO was stable in the ambient when compared with uncoated ZnO. WGM resonance from the exciton related emission, the enhancement in WGMs, and stability in the ambient condition of the Au-coated ZnO microrods suggest great potential for small-volume devices and microlasers.

Laser-assisted doping of intrinsic silicon carbide (SiC) films deposited on Si (100) substrates by pulsed laser deposition (PLD) method and its influence on simultaneous annealing of the thin film is studied. PLD grown intrinsic SiC films are transformed to p-type SiC and n-type SiC, using laser-assisted doping in aqueous aluminum chloride and phosphoric solutions, respectively. Simultaneous doping and annealing of the SiC film are observed during laser-assisted doping. By precisely positioning the selectively doped region, lateral p–n diodes are formed on the SiC films without using any mask. Electric characteristics confirmed the formation of a lateral p–n diode structure. Numerical analysis of temperature distribution along the depth of the SiC films explains the mechanism of simultaneous doping and annealing during the laser treatment.

Discovery of two-dimensional (2D) topological insulators (TIs) demonstrates tremendous potential in the field of thermoelectric since the last decade. Here, we have synthesized 2D TI, Sb2Te3 of various thicknesses in the range 65–400 nm using mechanical exfoliation and studied temperature coefficient in the range 100–300 K using micro-Raman spectroscopy. The temperature dependence of the peak position and line width of phonon modes have been analyzed to determine the temperature coefficient, which is found to be in the order of 10–2 cm−1/K, and it decreases with a decrease in Sb2Te3 thickness. Such low-temperature coefficient would favor to achieve a high figure of merit (ZT) and pave the way to use this material as an excellent candidate for thermoelectric materials. We have estimated the thermal conductivity of Sb2Te3 flake with the thickness of 115 nm supported on 300-nm SiO2/Si substrate which is found to be ~ 10 W/m–K. The slightly higher thermal conductivity value suggests that the supporting substrate significantly affects the heat dissipation of the Sb2Te3 flake.

With the 200 keV N+-ion implantation technique and a systematic variation of fluence, we report on the formation of highly conducting n-type diamond where insulator-to-metal transition (IMT) is observed above a certain fluence wherein the conductivity no longer obeys the hopping mechanism of transport rather, it obeys quantum corrections to Boltzmann conductivity at concentrations of nN ≥ 2 × 1020 cm−3. The conductivity for ultra-nanocrystalline diamond is found to be high, ∼650 Ω−1 cm−1 with thermal activation energy Ea ∼ 4 meV. Interestingly, with gradual increase in fluence, the conductivity in polycrystalline diamond films has been seen to progress from the hopping mechanism of transport in the case of low fluence implantation to a semiconducting nature with medium fluence and finally a semi-metallic conduction is observed where percolation occurs giving an insulator-to-metal transition. XANES confirms that the long-range order in diamond films remains intact when implanted with low and medium fluences; while implantation at sufficiently high fluences >5 × 1016 cm−2 leads to the formation of a disordered tetrahedral amorphous carbon network leading to metallic conduction resembling a metallic glass behaviour. XPS confirms that the sp2 fraction increases gradually with fluence starting from only 6% in the case of low fluence implantations and saturates at 40–50% for implantation at high fluences. A similar observation can be made for single crystal diamond when implanted at high fluence; it retains long-range order but percolative transport takes place through defects or semi-amorphized regions.

Wrinkles significantly influence the physical properties of layered 2D materials, including graphene. In this work, we examined thermal transport across wrinkles in vertical assemblies of few-layer graphene crystallites using the Raman optothermal technique supported by finite-element analysis simulations. A high density of randomly oriented uniaxial wrinkles were frequently observed in the few-layer graphene stacks which were grown by chemical vapor deposition and transferred on Si/SiO2 substrates. The thermal conductivity of unwrinkled regions was measured to be, κ ∼ 165 W m−1 K−1. Measurements at the wrinkle sites revealed local enhancement of thermal conductivity, with κ ∼ 225 W m−1 K−1. Furthermore, the total interface conductance of wrinkled regions decreased by more than an order of magnitude compared to that of the unwrinkled regions. The physical origin of these observations is discussed based on wrinkle mediated decoupling of the stacked crystallites and partial suspension of the film. Wrinkles are ubiquitous in layered 2D materials, and our work demonstrates their strong influence on thermal transport.

In this report, we investigate the annealing effects on microcrystalline diamond thin films of 1 μm thickness grown on silicon substrate by hot filament chemical vapor deposition technique. Annealing is important from the perspective of etching away the non-diamond/graphitic phase situated mainly at the grain boundaries to yield a high-quality continuous diamond film with higher sp3 %. From the Raman spectroscopy and also from the morphology of the films, we could see that with annealing in air, the degradation of the sp2 component sets in at around 500 °C leaving behind the sp3 component in the films, however the films are completely oxidised with annealing at 700 °C. Our results show that annealing at 500 °C has been able to etch away the sp2 phase efficiently as evident from the Raman spectroscopic analysis making the characteristic diamond peak more intense compared to graphitic peaks and also led to the decrease in FWHM of the diamond peak. The photoluminescence properties reveal the presence of silicon-vacancy centers in the film whose zero-phonon line (ZPL) shows a drastic decrease in the FWHM as we anneal at higher temperatures of more than 700 °C.

Silicon carbide (SiC) thin films were grown by pulsed laser deposition (PLD) on Si (1 0 0) substrates at a substrate temperature of 800 °C. Besides, laser annealing was performed on the post deposited intrinsic amorphous SiC films using Nd3+:YAG 355 nm laser in the Ar environment. The laser-annealed samples showed the crystalline characteristics. Crystalline characteristics of PLD grown, laser annealed samples were identified by X-ray diffraction (XRD), Raman analysis. Numerical analysis performed on SiC/Si interface to investigate the temperature distribution, to understand the mechanism of laser assisted annealing.

High-performance solar-blind photo-detection using highly transparent CuO nanostructures (with a bandgap of 4.15 eV) has been demonstrated. The device shows the dark current as low as 0.2 nA (−10 V applied bias) and no signature of breakdown even at a bias up to ±175 V. The device has shown record photo-sensitivity of 610, photo-responsivity of 14.02 A/W and photo-detectivity of $3.59\times 10 ^{13}$ cmHz 1/2W−1 in the UV-C region. The ratio of photo-responsivities at 210 nm and 500 nm i.e. R210/R500 was found to be $5.05\times 10 ^{4}$ . Additionally, the device has shown external quantum efficiency of ~5900 % at 210 nm excitation. This letter will establish CuO as one of the most promising ultra-wide bandgap semiconductors for cost-effective solar blind photo-detection.

We propose a method for substrate surface texturing with shallow micro structures (such as cylinders) made up of cross-linked SU8 2005 photoresist on glass substrates for conformal growth of thin films of functional materials. In this work, the textured substrates were used for the growth of antimony selenide (Sb2Se3) solar absorber and its properties were studied in comparison with films on plain glass substrates. Cross-linked SU8 2005 structures, i.e., an array of equally spaced cylinders having the dimensions of 100 µm/70 µm/40 µm diameter and 5 µm height, were introduced over an area of 20 mm × 20 mm on glass substrates via optical lithography process. Thin films of Sb2Se3 were grown above the textured surface using e-beam evaporation covering the glass-like resist structures underneath. Optical microscopy, scanning electron microscope (SEM) and optical profiler analyses confirm the morphological integrity of the Sb2Se3 absorber layer grown on textured substrates. Raman spectra were collected on plain and textured samples to probe the structural uniformity. The optical absorbance data of Sb2Se3 thin films grown on plain and periodically textured glass substrates were investigated using UV–Vis-NIR spectroscopy to study the effects of substrate texturing.

Gold nanoparticles (AuNPs) and gold nanoclusters (AuNCs) are gaining interest in medical diagnosis and therapy as they are bio-compatible and are easy to functionalize. Their interaction with radiofrequency (RF) field for hyperthermia treatment is ambiguous and needs further investigation. A systematic study of the absorption of capacitive RF field by AuNPs and AuNCs dispersed in phosphate-buffered saline (PBS) is reported here in tissue mimicking phantom. The stability of AuNPs and AuNCs dispersed in PBS was confirmed for a range of pH and temperature expected during RF hyperthermia treatment. Colloidal gold solutions with AuNPs (10 nm) and AuNCs (2 nm), and control, i.e. PBS without nanogold, were loaded individually in 3 ml wells in a tissue phantom. Phantom heating was carried out using 27 MHz short-wave diathermy equipment at 200 and 400 W for control and colloidal gold solutions. Experiments were conducted for colloidal gold at varying gold concentrations (10-100 µg/ml). Temperature rise measured in the phantom wells did not show dependence on the concentration and size of the AuNPs. Furthermore, temperature rise recorded in the control was comparable with the measurements recorded in both nanogold suspensions (2, 10 nm). Dielectric property measurements of control and colloidal gold showed3% difference in electrical conductivity between the control and colloidal gold for both nanoparticle sizes. From the measurements, it is concluded that AuNPs and AuNCs do not enhance the absorption of RF-capacitive field and power absorption observed in the biological medium is due to the ions present in the medium.

We report synthesis of Copper Zinc Tin Sulfide (CZTS) thin films using sequential evaporation technique. The as-deposited films were subjected to various sulfurization temperatures ranging from 520 °C to 640 °C. This paper presents a detailed analysis of temperature dependent phase and defect formation in Cu-rich off-stoichiometric CZTS thin films. CZTS thin films moved from F-type to C-type with decreasing Cu/Zn disorder and defect concentration with increasing sulfurization temperature. The resulting films showed less off-stoichiometry in contrast to initial choice of intended off-stoichiometry exhibiting the structural flexibility within the compositional limits. Despite being off-stoichiometric, all the samples exhibited the tetragonal CZTS phase with preferred orientations. Raman analysis showed the disappearance and reappearance of secondary phases with increasing sulfurization temperature. EDS analysis suggested that composition of the films moved towards better stoichiometry till 580 °C before deteriorating again. Composition and lattice parameter values suggested Cu-rich off-stoichiometric nature of sulfurized CZTS thin films. AFM study showed dependence of roughness with sulfurization temperature. Band gap was obtained in the range of 1.28 eV to 1.48 eV from UV–Vis spectroscopy measurement. PL analysis revealed the asymmetric shape and blue shift of the peaks. Band-to-tail recombination becomes pronounced with increase in sulfurization temperature. XPS analysis showed elements are in expected oxidation states.

Substitution of alkali earth metal ion of Sr2+, in the Pb2+ site of Pb(Mg1/3Nb2/3)O3–PbTiO3 is expected to induce functional modulations in the system. Doping of 4 at.% of Sr2+ in 0.68PMN-0.32PT was carried out to lower the transition temperature, and to investigate the intended ferroelectric and dielectric variations. Excellent relaxor property was observed in the doped sample without appreciable reduction in remnant polarization. Doping with Sr2+ led to a reduction in transition temperature from 165 °C to 117 °C. Doped sample exhibited remnant polarization Pr = 16.2 μC/cm2, Squareness factor (Rsq) = 1.05 and Relaxor exponent (γ) around 2. Modulation in the functional response was exhibited by the doped composition, having low transition temperature, and its prospect in electrocaloric applications was analyzed.

Persistent photoconductivity (PPC) in solution-processed pristine CuO and Au coated CuO thin films have been studied. Long-lasting PPC has been observed in Au coated CuO thin films with stable current levels even for 7 days. For the first time, long-lasting PPC effect in Au/CuO has been utilized for non-volatile optical memory. We have established both the SET and RESET processes using optical excitation. For the SET process, deep UV illumination ( $\lambda _{\mathrm {ex}}=254$ nm) was used while for the RESET, NIR ( $\lambda _{\mathrm {ex}}=800$ nm) excitation was used. In addition to the optical reset, low-temperature annealing (50 °C) was utilized for resetting the device. PPC effect in Au/CuO films has enormous possibility for next-generation commercial optical memory devices and neuromorphic computing.

The continuous depletion of fossil fuels and the increasing demand for eco-friendly and sustainable energy sources have prompted researchers to look for alternative energy sources. The loss of thermal energy in heat engines (100 °C–350 °C), coal-based thermal plants (150 °C–700 °C), heated water pumping in the geothermal process (150 °C–700 °C), and burning of petrol in the automobiles (150 °C–250 °C) in form of untapped waste-heat can be directly and/or reversibly converted into usable electricity by means of charge carriers (electrons or holes) as moving fluids using thermoelectric (TE) technology, which works based on typical Seebeck effect. The enhancement in TE conversion efficiency has been a key challenge because of the coupled relation between thermal and electrical transport of charge carriers in a given material. In this review, we have deliberated the physical concepts governing the materials to device performance as well as key challenges for enhancing the TE performance. Moreover, the role of crystal structure in the form of chemical bonding, crystal symmetry, order–disorder and phase transition on charge carrier transport in the material has been explored. Further, this review has also emphasized some insights on various approaches employed recently to improve the TE performance, such as, (i) carrier engineering via band engineering, low dimensional effects, and energy filtering effects and (ii) phonon engineering via doping/alloying, nano-structuring, embedding secondary phases in the matrix and microstructural engineering. We have also briefed the importance of magnetic elements on thermoelectric properties of the selected materials and spin Seebeck effect. Furthermore, the design and fabrication of TE modules and their major challenges are also discussed. As, thermoelectric figure of merit, zT does not have any theoretical limitation, an ideal high performance thermoelectric device should consist of low-cost, eco-friendly, efficient, n- or p-type materials that operate at wide-temperature range and similar coefficients of thermal expansion, suitable contact materials, less electrical/thermal losses and constant source of thermal energy. Overall, this review provides the recent physical concepts adopted and fabrication procedures of TE materials and device so as to improve the fundamental understanding and to develop a promising TE device.

In the present work, brownmillerite KBiFe2O5 (KBFO), a relatively new multifunctional compound, has been explored as an electrode material for applications in supercapacitors. Polycrystalline KBFO is synthesized via citrate combustion method. The phase formation, crystallinity, composition and morphology of KBFO samples are investigated using XRD, HRTEM, XPS and FESEM. As synthesized KBFO sample possesses rectangular rod-like morphology with monoclinic crystal system. The electrochemical properties of KBFO were analyzed using Galvanostatic charge/discharge (GCD), Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in acidic, alkaline and neutral electrolyte media. GCD results show a promising energy storage property with remarkable 100% capacitive retention after 1000 cycles. CV results also establish the pseudocapacitive nature of KBFO in all electrolyte media. These features support the feasibility of exploitation of KBFO for advanced energy storage applications.

Here, we report the fabrication of ZnO/p-GaN based high responsivity ultraviolet (UV) photodetector. Hydrothermal technique has been followed to grow ZnO nanorods; where two different types of precursors (nitrate and chloride) were used for the growth of nanorods. Interestingly, it was found that the ZnO nanorods grown using nitrate precursor are less prone to defect emission in comparison to the ZnO nanorods prepared using chloride-based precursor which resulted in low dark current levels. The photo-responsivity and photo-detectivity values of the as-fabricated device were calculated to be 350 mA W−1 and 3.5 × 1011 Jones, respectively at 360 nm excitation wavelength and ∼1.79 µW cm−2 excitation intensity. The demonstration of high responsivity UV detectors (at low excitation intensity values) using ZnO nanorods/GaN can pave the way toward the development of high-performance next generation UV photodetectors.

Extensive piezoresponse force microscopy (PFM) and magnetic force microscopy (MFM) measurements in conjunction with piezoresponse spectroscopy have been carried out on pellets of Bi

Since the discovery of Graphene, 2D materials have attracted wide research curiosity due to their unique properties and potential applications. The new class of 2D materials such as transition metal dichalcogenides (TMDs) is gaining tremendous popularity due to its intrinsic bandgap, while single-layer graphene lacks a finite bandgap and is considered a bottleneck for various electronic applications. In recent years, MoS2 and WS2 have widely explored TMDs for fundamental properties and applications due to the intrinsic bandgap and high carrier mobility. To demonstrate the realisation of 2D materials, various growth mechanisms were developed, including mechanical exfoliation, liquid-phase exfoliation, chemical vapour deposition (CVD), and so on. However, a bottom-up physical vapour deposition technique, especially pulsed laser deposition (PLD) was routinely utilised for complex oxide thin film growth and can be considered a potential alternative to commonly reported CVD method for realising 2D layers. Large-scale device fabrication of 2D materials and thus the commercialisation of these materials requires a large area growth mechanism. In the present work, the wafer-scale growth of 2D TMDs such as MoS2 and WS2 is discussed. Raman spectroscopy is used to identify the number of layers of the grown thin films.

In this study we investigated the ferroelectric and piezoelectric behaviour of co-sintered magnetoelectric composite fabricated by tape-casting method using Pb(1-x-3y/2)SrxLay(Zrz,Ti(1-z))O3 piezoelectric ceramic with x = 0.06, y = 0.03, z = 0.56 (PSLZT) multilayer and Ni0.6Zn0.4Fe2O4 (NZFO). PSLZT and NZFO powders were prepared by solid state reaction method and respective thick films were fabricated by tape casting method. PSLZT multilayer with Pt inner electrodes were laminated with NZFO and co-sintered at 1060 °C for 2 h to obtain delamination free layered composite. Scanning electron microscopy was employed to analyse the microstructure and interface of the co-sintered multilayer which are crucial for elastic coupling. Micrographs recorded across the cross section of the composites revealed insignificant interdiffusion between the phases. Individual piezoelectric multilayer and magnetoelectric composites were analysed for their ferroelectric behaviour. Piezo Force Microscopy (PFM) and Magnetic Force Microscopy (MFM) were utilized to study the ferroelectric domains and magnetic domains on top surface of PSLZT multilayer and NZFO, respectively in composite structure. Ferroelectric behaviour of PSLZT multilayer - NZFO composite was recorded and compared with 3 layered PSLZT. The values of remanent polarization were found to be 50.6 μC/cm2 and 55 μm/cm2 whereas capacitance at 1 Hz found to be 31.5 nF and 28.9 nF for PSLZT multilayer and PSLZT multilayer – NZFO composite respectively. Piezoelectric coefficient of PSLZT multilayer was found to be 980–1030 pC/N whereas for PSLZT multilayer – NZFO composites it was 1050–1150 pC/N. Magnetoelectric coefficient of 150 mV/cm.Oe was obtained for the same composite structure.

We have made an attempt to fabricate free standing warpage free PZT thick films of 100 µm thickness by tape casting method. The poly crystalline nature and nanoscale polarization switching of free ...

We demonstrate high performance broadband UV-to-NIR detection, which is a critical issue associated with ZnO-based photodetectors. The as-synthesized ZnO-ZnCr2O4 nanowalls were first time utilized for broadband, i.e., 250–850 nm photo-detection (both in front and back illumination configurations). The dark current was found to be as low as 0.12 nA. The device has shown peak sensitivity for the UV region ( $\lambda _{\mathrm {ex}}= {350}$ nm) with the photo-sensitivity of $\sim 1.28\times 10^{5}$ , photo-responsivity of 5.49 AW−1, photo-detectivity of $1.91\times 10^{13}$ cmHz1/2W−1, linear dynamic range of 82 dB, and external quantum efficiency of 1900%. In addition, the white light emission (CIE coordinates of 0.32 and 0.34) was also observed in the ZnO-ZnCr2O4 nanowalls. This letter will open new directions in oxide semiconductors-based optoelectronic devices.

We report on the fabrication of ZnO and Zn0.9Mg0.1O microrods using nanoparticle assisted pulsed laser deposition (NAPLD). Micro-photoluminescence studies reveal that Zn0.9Mg0.1O microrods exhibited a blue shift in the ultraviolet (UV) emission relative to unintentionally doped ZnO that was attributed to the increase in bandgap due to Mg doping. High-resolution micro-photoluminescence clearly indicated the presence of whispering gallery modes (WGMs) for both ZnO and Zn0.9Mg0.1O. Transverse electric (TE) and transverse magnetic (TM) optical WGMs were identified using the existing plane-wave model. The observation of lower order WGM modes in Zn0.9Mg0.1O microrods may be of great interest for future UV WGM lasing.

Polymer/lead zirconate titanate {[Pb(Zrx, Ti1-x)O3], PZT, x = 0.40} flexible composite films are prepared by solvent evaporation technique. Carbon tape used as a top and bottom electrodes for fabricating flexible PZT composite films. The phase purity and functional groups of PZT and polymer humps are confirmed by XRD and FTIR respectively. XPS analysis showed that PMMA contains carbon (C) and oxygen (O). Carbon (C), oxygen (O), lead (Pb), zirconium (Zr) and titanium (Ti) are present in PZT/PMMA composite films. The chemical states of Pb, Zr and Ti ions are 2+, 4+ and 4+ respectively confirmed by XPS. The higher forefinger bending motion of the film is found to reveal greater output voltage (5.2 V) than the output voltage (1.6 V) for slight bending motion of the forefinger. Therefore, based on the results human mechanical forces induce compressive stress on PZTs ferroelectric based composite films and are excellent candidate for energy harvester.

Machining of Al-SiC metal matrix composite (MMC) is still being a challenging task in the automotive and aerospace sector due to its frequent tool wear while processing this MMC. The hard Polycrystalline diamond tools (PCD) are used as a cutting tool in many sectors for machining of MMC. But the usage of PCD is commercially not viable due to its high cost involved in the fabrication. In this regard, low-cost diamond-coated tungsten carbide (WC-Co) tools are considered as an alternative to PCD. However, the diffusion of cobalt from WC-Co during diamond deposition promotes higher graphitization at the diamond-carbide interface. This induces coating delamination during MMC machining. This outward diffusion of cobalt can be hindered by doping boron in the diamond lattice to enhance adhesion strength of the coating. Hence in this work, the boron doped graded layer diamond coating (BDD/transition layer/NCD) on WC-Co was proposed to improve the machining performance of MMC. In this work, four different CVD diamond coated WC-Co tools such as microcrystalline diamond coating (MCD), nano-crystalline diamond coating (NCD), boron-doped diamond coating (BDD) were considered for comparison along with the proposed tools. The different phases (sp3 and sp2) in the diamond coating were analyzed through cross-sectional Raman mapping technique. The Rockwell indentation test confirms that the better adhesion strength obtained in BMTN coated tools. The wear behavior of these diamond coated tools was tested by machining of AA2124/25%SiCp material. In addition, performances of these tools were compared with widely accepted industrial grade PCD tools. The temperature at the cutting zone, chip morphology and surface roughness of the machined component were studied through an appropriate test method. The occurrence of edge chipping while machining was continuously monitored through acoustic emission (AE) signals. The machining results show that BMTN coated tool exhibits least tool wear (VB = 0.25 mm) in comparison with MCD (VB=0.47 mm), NCD (VB=0.57 mm), BDD (VB= 0.33 mm) coated tools and PCD (VB = 0.29 mm) tools respectively. In addition, the results of AE signals show that MCD, NCD coated tools and PCD tools undergone edge chipping whereas there was no edge chipping observed in BDD and BMTN tools. Thus Nano –Engineered BMTN tools observed to be a preferred cutting tool for efficient machining of Al-SiC MMC material.

Cubic silicon carbide (3C-SiC) films were grown by pulsed laser deposition (PLD) on magnesium oxide [MgO (100)] substrates at a substrate temperature of 800°C. Besides, p-type SiC was prepared by laser assisted doping of Al in the PLD grown intrinsic SiC film. The SiC phases, in the grown thin films, were confirmed by x-ray diffraction (XRD), Si–C bond structure is identified by Fourier-transform infrared spectroscopy spectrum analysis. Measurements based on the XRD and Raman scattering techniques confirmed improvement in crystallization of 3C-SiC thin films with the laser assisted doping. The studies on I–V characteristics by two probe technique, elemental analysis by energy dispersion spectrum, binding energy by x-ray photoelectron spectroscopy and carrier concentration by Hall effect, ensured Al doping in SiC thin film. From the UV–visible NIR spectroscopic analysis, the optical bandgap of the PLD grown 3C-SiC was obtained. Numerical analysis of temperature and carrier concentration distribution is simulated to understand the mechanism of laser assisted doping.

International audience; We explored the time dependence of the nanoscale domain relaxation mechanism in epitaxial K0.5Na0.5NbO3 (KNN) thin films grown on La0.67Sr0.33MnO3/SrTiO3 (001) substrates over the thickness range 20− 80 nm using scanning probe microscopy. Kelvin probe force microscopy (KFM) and piezoresponse force microscopy were performed on pulsed-laser-deposition-deposited KNN thin films for studying the time evolution of trapped charges and polarized domains, respectively. The KFM data show that the magnitude and retention time of the surface potential are the maxima for 80 nm-thick film and reduce with the reduction in the film thickness. The charging and discharging of the samples reveal the easier and stronger electron trapping compared to hole trapping. This result further indicates the asymmetry between retention of the pulse-voltage-induced upward and downward domains. Furthermore, the time evolution of these ferroelectric nanodomains are found to obey stretched exponential behavior. The relaxation time (T) has been found to increase with increase in thickness; however, the corresponding stretched exponent (β) is reduced. Moreover, the written domain can retain for more than 2300 min in KNN thin films. An in-depth understanding of domain relaxation dynamics in Pb-free KNN thin films can bridge a path for future high-density memory applications.

Collective behaviour of electrons, frustration induced quantum fluctuations and entanglement in quantum materials underlie some of the emergent quantum phenomena with exotic quasi-particle excitations that are highly relevant for technological applications. Herein, we present our thermodynamic and muon spin relaxation measurements, complemented by ab initio density functional theory and exact diagonalization results, on the recently synthesized frustrated antiferromagnet Li4CuTeO6, in which Cu2+ ions (S = 1/2) constitute disordered spin chains and ladders along the crystallographic [101] direction with weak random inter-chain couplings. Our thermodynamic experiments detect neither long-range magnetic ordering nor spin freezing down to 45 mK despite the presence of strong antiferromagnetic interaction between Cu2+ moments leading to a large effective Curie-Weiss temperature of − 154 K. Muon spin relaxation results are consistent with thermodynamic results. The temperature and magnetic field scaling of magnetization and specific heat reveal a data collapse pointing towards the presence of random-singlets within a disorder-driven correlated and dynamic ground-state in this frustrated antiferromagnet.