Tuning the physiochemical properties of polycaprolactone-hydroxyapatite composite films by gamma irradiation for biomedical applications.

Physiochemical properties of polycaprolactone-hydroxyapatite (PCL-HAp) composites were investigated in the pristine and after irradiation of γ rays (25, 50, 75, and 100 kGy). PCL-HAp composites were synthesized by solvent evaporation and characterized using spectroscopic methods as well as biological assays. The surface roughness (RMS) of the irradiated composite film (at 75 kGy) was 80 times higher than that of the pristine. Irradiation tailors the contact angle of the films from 77° to 90° (at 100 kGy). A decrease in particle size (at 100 kGy) of HAp nanorods in PCL-HAp composites film was observed. The XRD peak of PCL was slightly shifted from 21.2° to 21.7° (at 100 kGy) with the decrease in crystallite size. The peak intensity of the PCL and HAp altered on irradiation that was confirmed by FTIR and Raman analysis. Further, the bandgap of the irradiated film was lowered by 13 % (at 25 kGy). The luminescence intensity decreased due to the non-radiative process induced by the irradiation defects. All the samples possess hemocompatibility percentage of <10 % as per ASTM standards. At 75 kGy, fibroblast cell proliferation was higher than the pristine and other doses. The gamma-irradiated PCL-HAp composite films are potential candidates for tissue engineering applications.

Probing size-dependent defects in zinc oxide using synchrotron techniques: impact on photocatalytic efficiency.

In the present study, synchrotron-based X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS) and X-ray excited optical luminescence (XEOL) have been used to investigate the induced defect states in metal oxide nanomaterials. Specifically, two synthesis approaches have been followed to develop unique nano-sized peanut-shaped (N-ZnO) nanostructures and micron-sized hexagonal rods (M-ZnO). XANES analysis at the Zn K-edge revealed the presence of defect states with a divalent oxidation state of zinc (Zn2+) in a tetrahedral structure. Furthermore, XAS measurements performed at the Zn L3,2-edge and O K-edge confirm higher oxygen-related defects in M-ZnO, while N-ZnO appeared to have a higher concentration of surface defects due to size confinement. Moreover, the in-line XEOL and time dependent-XEOL measurements exposed the radiative excitonic recombination phenomena occurring in the band-tailing region as a function of absorption length, X-ray energy excitation, and time. Based on the chronology developed in the defect state improvement, a possible energy band diagram is proposed to accurately locate the defect states in the two systems. Furthermore, the increased absorption intensity at the Zn L3,2-edge and the O K-edge under the UV lamp suggests delayed recombination of electrons and holes, highlighting their potential use as photo catalysts. The photocatalytic activity degrading the rhodamine B dye established M-ZnO as a superior catalyst with a rapid degradation rate and significant mineralization. Overall, this work provides valuable insights into ZnO defect states and provides a foundation for efficient advanced materials for environmental or other optoelectronic applications.

Intriguing physicochemical properties and impact of co-dopants on N-doped graphene oxide based ZnS nanowires for photocatalytic application.

Superparamagnetic N-doped graphene oxide (GO)- with ZnS nanowires was synthesized by a one-step hydrothermal method by doping dilute amounts of Ga, Cr, In, and Al ions for water treatment and biomedical applications. In these experiments, to enhance their properties, 2% of Ga3+, In3+, and or Al3+ were codoped along with 2% Cr ions in these ZnS nanowires. The nanocomposite with the composition, In0.02Cr0.02Zn0.96S, has better photocatalytic efficiency than other co-doped nanocomposites. The In (metalloids) and Cr (transition metal ion) are the best combinations to increase the magnetic properties which are beneficial for photocatalytic activity. Synthesized nanocomposite materials were characterized by several techniques such as X-ray diffraction, Field emission-scanning electron microscope (FESEM) with EDAX, vibrating sample magnetometer (VSM), UV-Vis, X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy. The correlation of intriguing magnetic properties with their photocatalytic properties is also discussed. XPS was employed for the detection of surface defects, phase transformation, and the nature of chemical components present in the nanocomposites. The Frankel and substitutional defects have a direct impact on photocatalytic activity that was determined from the fluorescence (FL) spectroscopy. FL and XPS reveal that the Cr and In codoped composite has a higher percentage of defects hence its photocatalytic efficiency reaches 94.21%.

Evaluation of one-year effectiveness of clobazam as an add-on therapy to anticonvulsant monotherapy in participants with epilepsy having uncontrolled seizure episodes: An Indian experience.

OBJECTIVES: To prospectively study the effectiveness and safety of clobazam as an add-on therapy in patients with epilepsy whose seizures are not adequately controlled with antiseizure medicine (ASM) monotherapy. METHODS: We conducted a prospective, observational study at 28 neurology outpatient clinics in India from June 2017 to October 2019. Consecutive patients with epilepsy (older than 3 years) with inadequate seizure control with ASM monotherapy were initiated on clobazam. Patients were followed up at 1, 3, 6, 9, and 12 months. Seizure control and adverse events were assessed through personal interviews and seizure diaries. RESULTS: Out of 475 eligible patients, data of 429 patients (men: 65.5%) were evaluated (46 excluded due to protocol deviations). The median age was 25 (range, 3-80 years) years and the median duration of epilepsy was 3 (0.1-30) years. The majority of patients had focal epilepsy (55.0%) and genetic generalized epilepsy (40.1%). The one-year follow-up was completed by 380 (88.5%) patients. At one-year follow-up, 317 (83.4%; N = 380) patients in the study remained seizure free. These 317 patients who were seizure free at 12 months comprised 73.9% of the evaluable population (N = 429). In 98.8% of patients, the primary reason for adding clobazam was inadequate control of seizures with treatment. During one-year follow-up, a total of 113 (22.6%) patients experienced at least one adverse event which included 103 (20.6%) patients who experienced 386 episodes of seizures. CONCLUSION: The study provides preliminary evidence that clobazam is effective and well-tolerated as add-on therapy for a period of one year among patients with epilepsy inadequately stabilized with monotherapy. TRIAL REGISTRATION NUMBER: CTRI/2017/12/010906.

Testing for nonlinearity in nonstationary time series: A network-based surrogate data test.

The classical surrogate data tests, which are used to differentiate linear noise processes from nonlinear processes, are not suitable for nonstationary time series. In this paper, we propose a surrogate data test that can be applied on both stationary time series as well as nonstationary time series with short-term fluctuations. The method is based on the idea of constructing a network from the time series, employing a generalized symbolic dynamics method introduced in this work, and using any one of the several easily computable network parameters as discriminating statistics. The construction of the network is designed to remove the long-term trends in the data automatically. The network-based test statistics pick up only the short-term variations, unlike the discriminating statistics of the traditional methods, which are influenced by nonstationary trends in the data. The method is tested on several systems generated by linear or nonlinear processes and with deterministic or stochastic trends, and in all cases it is found to be able to differentiate between linear stochastic processes and nonlinear processes quite accurately, especially in cases where the common methods would lead to false rejections of the null hypothesis due to nonstationarity being interpreted as nonlinearity. The method is also found to be robust to the presence of experimental or dynamical noise of a moderate level in an otherwise nonlinear system.

Local structure investigation of Co-Fe-Si-B ribbons by extended X-ray absorption fine-structure spectroscopy.

In the present work, extended X-ray absorption fine-structure (EXAFS) investigations of Co69FexSi21-xB10 (x = 3, 5, 7) glassy ribbons were performed at the Co K-edge. The magnitude of the first peak of the Fourier transforms of the EXAFS signals is found to increase monotonically with increasing Si concentrations indicating the formation of the localized ordered structure at the atomic scale. The Co-Si coordination number (CN) increases at the expense of the CN of Co/Fe. Smaller interatomic distances are observed in the glassy phase compared with that in the crystalline phase which promotes the stability of the glassy phase. Calculations of the thermodynamic parameter (PHSS), cohesive energy (EC) and the atomic radius difference (δ) parameter show that the alloy composition Co69Fe3Si18B10 has a good glass-forming ability (GFA) with the highest CN of Si compared with other compositions. A linear correlation of CN with that of the GFA parameter (PHSS) exists and the CN also plays a crucial role in the GFA of the glassy alloys. This parameter should be considered in developing different GFA criteria.

Thermoelectric properties of GaN with carrier concentration modulation: an experimental and theoretical investigation.

The present work investigates the less explored thermoelectric properties of the n-type GaN semiconductor by combining both experimental and computational tools. The Seebeck coefficients of GaN epitaxial thin films were experimentally measured in the wide temperature range from 77 K to 650 K in steps of ∼10 K covering both low and high-temperature regimes as a function of the carrier concentration (2 × 1016, 2 × 1017, 4 × 1017 and 8 × 1017 cm-3). The measured Seebeck coefficient at room temperature was found to be highest (-374 µV K-1) at the lowest concentration of 4 × 1016 cm-3, and decreases in magnitude monotonically (-327.6 µV K-1, -295 µV K-1, -246 µV K-1 for 2 × 1017, 4 × 1017, 8 × 1017 cm-3, respectively) as the sample carrier concentration increases. The Seebeck coefficient remains negative in the entire temperature range under study indicating that electrons are the dominant carriers. To understand the temperature-dependent behaviour, we also carried out the electronic structure and transport coefficient calculations using the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential and semiclassical Boltzmann transport theory implemented in WIEN2k and BoltzTraP code, respectively. The experimentally observed carrier concentrations were used in the calculations. The estimated results obtained under constant relaxation time approximations provide a very good agreement between the theoretical and experimental data of Seebeck coefficients in the temperature range from 260 to 625 K.

Structural, magnetic and dielectric properties in 3d-5dbased Sr2FeIrO6thin films.

The structural, magnetic and dielectric properties have been investigated in 3d-5dbased double perovskite Sr2FeIrO6thin films deposited by pulse laser deposition technique. To understand the effect of strain, epitaxial films are grown with varying thickness as well as on different substrates i.e., SrTiO3(100) and LaAlO3(100). The films with highest thickness are found to be more relaxed. Atomic force microscope images indicate all films are of good quality where grain sizes increase with increase in film thickness. X-ray absorption (XAS) spectroscopy measurements indicate a Ir5+charge state in present films while providing a detailed picture of hybridization between Fe/Ir-dand O-porbitals. The bulk antiferromagnetic transition is retained in films though the transition temperature shifts to higher temperature. Both dielectric constant (ϵr) and loss (tan δ) show change around the magnetic ordering temperatures of bulk Sr2FeIrO6indicating a close relation between dielectric and magnetic behaviors. A Maxwell-Wagner type relaxation is found to follow over whole frequency range down to low temperature in present film. On changing the substrate i.e., LaAlO3(100), theϵr(T) and (tan δ(T)) show almost similar behavior butϵrshows a higher value which is due to an increased strain coming from high mismatch of lattice parameters.

The effect of orbital-lattice coupling on the electrical resistivity of YBaCuFeO5 investigated by X-ray absorption.

Temperature-dependent X-ray absorption near-edge structures, X-ray linear dichroism (XLD) and extended X-ray absorption fine structure (EXAFS) spectroscopic techniques were used to investigate the valence state, preferred orbital and local atomic structure that significantly affect the electrical and magnetic properties of a single crystal of YBaCuFeO5 (YBCFO). An onset of increase of resistivity at ~180 K, followed by a rapid increase at/below 125 K, is observed. An antiferromagnetic (AFM)-like transition is close to the temperature at which the resistivity starts to increase in the ab-plane and is also observed with strong anisotropy between the ab-plane and the c-axis. The XLD spectra at the Fe L3,2-edge revealed a change in Fe 3d eg holes from the preferential [Formula: see text] orbital at high temperature (300-150 K) to the [Formula: see text] orbital at/below 125 K. The analysis of the Fe K-edge EXAFS data of YBCFO further revealed an unusual increase in the Debye-Waller factor of the nearest-neighbor Fe-O bond length at/below 125 K, suggesting phonon-softening behavior, resulting in the breaking of lattice symmetry, particularly in the ab-plane of Fe-related square pyramids. These findings demonstrate a close correlation between electrical resistivity and coupling of the preferred Fe 3d orbital with lattice distortion of a single crystal of YBCFO.

Nicotinamide adenine dinucleotide immobilized tungsten trioxide nanoparticles for simultaneous sensing of norepinephrine, melatonin and nicotine.

Herein, we report the anionic surfactant, ethylene diamine tetraacetic acid (EDTA), mediated synthesis of WO3 nanoparticles and its subsequent modification through gamma irradiation (GI) and electrochemical immobilization with nicotinamide adenine dinucleotide (NAD). Glassy carbon electrode (GCE) modified with GI-WO3 NPs and the enzyme NAD exhibited strong electro-oxidation of three important biomolecules such as norepinephrine (NEP), melatonin (MEL) and nicotine (NIC) in 0.1 M phosphate buffer saline (PBS) at physiological pH of 7. Square wave voltammetry (SWV) studies exhibited three well-defined peaks at potentials of 120, 570 and 840 mV, corresponding to the oxidation of NEP, MEL and NIC respectively, indicating that simultaneous determination of these compounds is feasible at the NAD/GI EDTA-WO3/GCE. The proposed sensor displayed a wide linear range of 0.010-1000 µM with the lowest detection limit of 1.4 nM for NEP, 2.6 nM for MEL and 1.7 nM for NIC respectively. Furthermore, the modified electrode was successfully applied to detect NEP, MEL and NIC in pharmaceutical and cigarette samples with excellent selectivity and reproducibility.

Strain effect on orbital and magnetic structures of Mn ions in epitaxial Nd0.35Sr0.65MnO3/SrTiO3 films using X-ray diffraction and absorption.

This study probes the temperature-dependent strain that is strongly correlated with the orbital and magnetic structures of epitaxial films of Nd0.35Sr0.65MnO3 (NSMO) that are fabricated by pulsed laser deposition with two thicknesses, 17 (NS17) and 103 nm (NS103) on SrTiO3 (STO) substrate. This investigation is probed using X-ray diffraction (XRD) and absorption-based techniques, X-ray linear dichroism (XLD) and the X-ray magnetic circular dichroism (XMCD). XRD indicates a significant shift in the (004) peak position that is associated with larger strain in NS17 relative to that of NS103 at both 30 and 300 K. Experimental and atomic multiplet simulated temperature-dependent Mn L3,2-edge XLD results reveal that the stronger strain in a thinner NS17 film causes less splitting of Mn 3d eg state at low temperature, indicating an enhancement of orbital fluctuations in the band above the Fermi level. This greater Mn 3d orbital fluctuation can be the cause of both the enhanced ferromagnetism (FM) as a result of spin moments and the reduced Néel temperature of C-type antiferromagnetism (AFM) in NS17, leading to the FM coupling of the canted-antiferromagnetism (FM-cAFM) state in NSMO/STO epitaxial films at low temperature (T = 30 K). These findings are also confirmed by Mn L3,2-edge XMCD measurements.

Effect of Fe ion implantation on the thermoelectric properties and electronic structures of CoSb3 thin films.

In the present study, thin films of single-phase CoSb3 were deposited onto Si(100) substrates via pulsed laser deposition (PLD) method using a polycrystalline target of CoSb3. These films were implanted by 120 keV Fe-ions with three different fluences: 1 × 1015, 2.5 × 1015 and 5 × 1015 ions per cm2. All films were characterised by X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), Rutherford backscattering (RBS) spectrometry and X-ray absorption spectroscopy (XAS). XRD data revealed that the ion implantation decreased the crystalline nature of these films, which are recovered after the rapid thermal annealing process. The Seebeck coefficient S vary with the fluences in the temperature range of 300 K to 420 K, and is found to be highest (i.e., 254 µV K-1) at 420 K for the film implanted with 1 × 1015 ions per cm2. The high S and low resistivity lead to the highest power factor for the film implanted with 1 × 1015 ions per cm2 (i.e., 700 µW m-1 K-2) at 420 K. The changing of the sign of S from negative for the pristine film to positive for the Fe-implanted samples confirm that the Fe ions are electrically active and act as electron acceptors by replacing the Co atoms. XAS measurements confirm that the Fe ions occupied the Co site in the cubic frame of the skutterudite and exist in the 3+ oxidation state in this structure.

Influence of defect structure on colour tunability and magneto optical behaviour of WO3 nanoforms.

The present study reports the impact of thermal annealing on the structural, optical and magnetic properties of WO3 nanostructures, synthesized using an acid precipitation method by, employing various spectroscopic and magnetic measurements. The X-ray diffraction and Raman measurements confirmed the orthorhombic structure of as dried WO3·H2O and monoclinic structure of WO3 nanopowders annealed at or above 500 °C. The morphological characterization shows the formation of different microstructures like nanosheets, nanoplatelets and nanocuboids in the micro-scale with the variation of annealing temperatures. The optical band gap has been calculated using the Kubelka-Munk function. The room temperature photoluminescence (PL) spectra recorded at different excitation wavelengths show intense near ultraviolet (NUV) emission which might be due to the presence of localized states associated with oxygen vacancies, and the surface states in the conduction band. The emissions in visible region correspond to the structural defects such as oxygen vacancies present within the band gap and band to band transitions. The spectral chromaticity colour coordinates indicate that the light emitted from the prepared samples shows shift from violet to red region with the change of excitation wavelength. Magnetic measurements show decrease in room temperature ferromagnetism (FM) with annealing temperature. The X-ray absorption spectroscopy (XAS) measurements at O K-edge show the significant change in the W-O hybridizations. The decrease in PL intensity and ferromagnetic ordering with increase in annealing temperatures are directly correlated with the filling up of oxygen vacancies in the samples. The oxygen vacancies based F-Center exchange model is discussed to understand the origin of FM in WO3 nanostructures.

Synthesis of OSL nanophosphor Li3B7O12:Mn and its dosimetric properties.

The present paper reports the structural, morphological and optical properties of nanophosphor Li3B7O12:Mn with an optimised dopant concentration of 0.25 mol% and its surface modification under the irradiation of 250 keV proton beams and gamma photons for ion fluence ranging from 1 × 1013 to 6.25 × 1015 ions cm-2 and doses from 100 mGy-100 Gy, respectively. This nanophosphor has been synthesised by the high temperature solid state reaction method. Its optical properties are characterised by optically stimulated luminescence (OSL) and thermo luminescence (TL) techniques. This nanophosphor is polycrystalline in nature with a grain size of 40-80 nm confirmed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The OSL decay and TL glow curve response of the proton beam irradiated samples exhibit significant intensity at a fluence of 2.5 × 1014 ions cm-2. Moreover, Li3B7O12:Mn displays a linear response for gamma doses in the range of 100 mGy-50 Gy. We have also investigated the reusability and reproducibility of this material. The above study demonstrates that Li3B7O12:Mn is a robust and promising candidate for medical proton dosimetry.

Origin of magnetic properties in carbon implanted ZnO nanowires.

Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.

Mechanistic insights into the interaction between energetic oxygen ions and nanosized ZnFe2O4: XAS-XMCD investigations.

The interactions of energetic ions with multi-cation compounds and their consequences in terms of changes in the local electronic structure, which may facilitate intriguing hybridization between O 2p and metal d orbitals and magnetic ordering, are the subject of debate and require a deep understanding of energy transfer processes and magnetic exchange mechanisms. In this study, nanocrystals of ZnFe2O4 were exposed to O7+ ions with an energy of 100 MeV to understand, qualitatively and quantitatively, the metal-ligand field interactions, cation migration and magnetic exchange interactions by employing X-ray absorption fine structure measurements and X-ray magnetic circular dichroism to get deeper mechanistic insights. Nanosized zinc ferrite nanoparticles (NPs) with a size of ∼16 nm synthesized in the cubic spinel phase exhibited deterioration of the crystalline phase when 100 MeV O7+ ions passed through them. However, the size of these NPs remained almost the same. The behaviour of crystal deterioration is associated with the confinement of heat in this interaction. The energy confined inside the nanoparticles promotes cation redistribution as well as the modification of the local electronic structure. Prior to this interaction, almost 42% of Zn2+ ions occupied AO4 tetrahedra; however, this value increased to 63% after the interaction. An inverse effect was observed for metal ion occupancies in BO6 octahedra. The L-edge spectra of Fe and Zn reveal that the spin and valence states of the metal ions were not affected by this interaction. This effect is also supported by K-edge measurements for Fe and Zn. The t2g/eg intensity ratio in the O K-edge spectra decreased after this interaction, which is associated with detachment of Zn2+ ions from the lattice. The extent of hybridization, as estimated from the ratio of the post-edge to the pre-edge region of the O K-edge spectra, decreased after this interaction. The metal-oxygen and metal-metal bond lengths were modified as a result of this interaction, as determined from extended X-ray absorption fine structure measurements. These measurements further support the observation of cation migration from AO4 tetrahedra to AO6 octahedra and vice versa. The Fe L-edge magnetic circular dichroism spectra indicate that Fe3+ ions occupying sites in AO4 tetrahedra and BO6 octahedra exhibited antiferromagnetic-like ordering prior to this interaction. The NPs that interacted with energetic O ions displayed a different kind of magnetic ordering.

Tuning of the Thermoelectric Properties of Bi2Te3 Nanorods Using Helium Ion Irradiation.

The present study reports an enhancement of the power factor of Bi2Te3 nanorods NRs) by helium (He+) ion irradiation. High-resolution transmission electron microscopy studies revealed the formation of amorphous layers on the surface of the NRs at the high ion fluence. This amorphous nature is due to the accumulation of migrating point defect clusters at the surface of the NRs. Raman scattering experiments provide further insight to the observed structural modifications. At higher ion fluence, impurity-dominated scattering processes significantly enhance the value of the Seebeck coefficient of Bi2Te3 NRs. The He+ ion irradiation up to the ion fluence of 1 × 1016 ions/cm2 improves the thermoelectric transport properties with the highest power factor, 8.2 µW/m K2, at 390 K. Further investigations may result in the possibility of fabricating the Bi2Te3 NRs as thermoelectric generators with a high power factor for space applications.

Current-voltage characteristics and electroresistance in LaMnO3-δ/La0.7Ca0.3MnO3/LaAlO3 thin film composites.

In this communication, we report results of the electrical transport properties across the interface of composites consisting of n-type LaMnO3-δ (LMO) and p-type La0.7Ca0.3MnO3 (LCMO) manganites grown on LaAlO3 (LAO) single crystalline substrates using low cost wet chemical solution deposition (CSD) and sophisticated, well-controlled dry chemical vapor deposition (CVD) chemical techniques. The XRD ϕ-scan studies reveal the single crystalline nature of both bilayered composites, with parallel epitaxial growth of LMO and LCMO layers onto the LAO substrate. The valence states of Mn ions in both layers of both composites were identified by performing X-ray photoelectron spectroscopy (XPS). The I-V characteristics of the LMO/LCMO interfaces show strong backward diode-like behavior at higher applied voltages well above the crossover voltage (VNB). Below VNB, the interfaces demonstrate normal diode-like characteristics throughout the studied temperature range. The electric field-induced modulation of the LMO/LCMO junction resistance of the interfaces has been observed. Electric field-dependent electroresistance (ER) modifications at different temperatures have also been studied. The electrical transport properties have been discussed in the context of various mechanisms, such as charge injection, tunneling, depletion region modification and thermal processes across the interface. The effects of structurally and chemically developed sharp interfaces between the LMO and LCMO layers on the transport properties of the presently studied bilayered thin film composites have been discussed on the basis of correlation between the physicochemical characterization and charge transport behavior. A comparison of different aspects of the transport properties has been presented in the context of the structural strain and crystallinity of the composites grown using both wet and dry chemical techniques.

Correction: Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films.

Correction for 'Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films' by Eesh Vaghela et al., Phys. Chem. Chem. Phys., 2017, DOI: 10.1039/c6cp07730g.

Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films.

In this communication, structural, microstructural, transport and magnetotransport properties are reported for La0.7Pb0.3MnO3/LaAlO3 (LPMO/LAO) manganite films having different thicknesses. All the films were irradiated with 200 MeV Ag+15 swift heavy ions (SHI). Films were grown using the sol-gel method by employing the acetate precursor route. Structural measurements were carried out using the X-ray diffraction (XRD) method at room temperature, while atomic force microscopy (AFM) was performed for the surface morphology. Temperature dependent resistivity under different applied magnetic fields for all the films shows metal to insulator transition at temperature TP. In addition to the metal to insulator transition at TP, the films also exhibit low temperature resistivity upturn behavior. Resistivity, TP and upturn behavior are highly influenced by the film thickness, applied magnetic field and irradiation. To understand the nature of charge transport for the low temperature resistivity behavior and metallic and insulating (semiconducting) regions, various models and mechanisms have been verified and the most suitable mechanism has been found for each region in the resistivity curves. Magnetoresistance (MR) is affected by temperature, film thickness and irradiation. MR behavior has been understood in terms of combined and separate contributions from grains and grain boundaries in the films.