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We have investigated the coupling of lattice with spin via strain interactions in the CoFe2O4/PMN-PT composite system. X-ray diffraction and Raman spectroscopic studies illustrate a remarkable modification in CoFe2O4lattice across Curie temperature (450 K) of PMN-PT. Subsequently, CoFe2O4/PMN-PT composite reveals a sudden drop in magnetic moment across Tc of PMN-PT (450 K). However,theindependent CoFe2O4phasedisplaystypical ferromagnetic behaviour across this temperature. These findings establish spin-lattice coupling owing to th interfacial strain transfer between CoFe2O4 and PMN-PT in composite. The strain intractions leads to magneto-electric coupling, evidenced by measuring magentization and magneto-electric coefficient for the electric field poled and unploed CoFe2O4/PMN-PT composite samples. X-ray magnetic circular dichroism (XMCD) analysis establishes that the cation (Fe3+/Co2+) redistribution occurs on tetrahedral and octahedral site in the electrically poled CoFe2O4/PMN-PT composite, confirming the coupling between magnetic and electric ordering in the composite. The magneto-electric coupling coefficient alpha vs dc magnetic field curves revealed hysteretic behavior and enhanced {\alpha} values after electric poling, which originates from the strain induced modifications in the magnetic domains configuration of composite in the poled samples. These findings suggest that the existence of spin lattice coupling may leads to the mechanism of strong magneto-electric effects via strain interactions in CoFe2O4/PMN-PT composite., Comment: 26 pages, 9 figures

India has the presence of about 635 tribal groups and sub-groups, including 73 so-called primitive tribes. Together they comprise nearly 8.2 per cent of the country's population. Tribals are often known by national terms such as native people, aboriginals, first nations, adivasi, janajati, hunter-gatherers, etc. Digital inclusion has the potential to uplift their status and bring them into the mainstream society. The Ministry of Tribal Affairs (MoTA) is responsible for planning, making policies, and coordinating program for the development and empowerment of India's Scheduled Tribe communities. Identifying the challenges and mapping out the potentialities are the key drivers for digital empowerment of the tribal communities in India. This paper is an attempt to trace out the issues, understand the potentialities, and provide suggestive measures for inclusion of tribals in the wave of digital revolution.

La0.7Sr0.3MnO3 (LSMO)/poly(vinylidenefluoride-co-trifluoroethylene)(P(VDF-TrFE) particulate nanocomposite films prepared to produce large magnetoelectric (ME) voltage at room temperature for multifunctional device applications. LSMO nanoparticles (NPs) were prepared by sol–gel auto-combustion method and these NPs belong to space group R-3c. LSMO/P(VDF-TrFE) (0–3) nanocomposite (NC) films were prepared by solution casting method for different volume percentage of LSMO in P(VDF-TrFE). Dielectric and DC leakage current density(J) analysis of these NCs reveal very small loss tangents (~ 0.01) and very small leakage current density J ~ 10−7 A/mm2 respectively, which further demonstrate the uniform distribution of NPs in P(VDF-TrFE) matrix. Room temperature M-H and low temperature M-T analysis of LSMO NPs confirm ferromagnetic nature with Curie temperature at ~ 368 K. LSMO/P(VDF-TrFE) NC films exhibit multiferroic properties up to 5% volume percentage of LSMO at room temperature. A maximum ME voltage 11.68 mV is produced corresponding to giant transverse ME voltage coefficient ( $${\alpha }_{31}^{V})$$ = 155.74 mVOe−1 cm−1 at DC magnetic field (Hdc) = 2.57 kOe and AC magnetic fileld(Hac) = 25Oe for 0.5% LSMO volume percentage NC films. A self bias ME voltage 11.3175 mV is observed at zero Hdc for 0.5% LSMO volume percentage NC films, which can be used inpotential ME devices.The variation of ME voltage coefficient $$\left({\alpha }^{V}\right)$$ at different angles between P and applied magnetic field(Hdc) for 0.5% LSMO NC films is also reported which shows $${\alpha }^{V}$$ is maximum at the angles 90o and 270o.

Magnetoelectric (ME) coupling properties of La0.7Ba0.3MnO3 (LBMO)/P (VDF-TrFE) (0–3) nano-composite films were investigated for device-oriented application like magnetic sensors, actuators, energy harvesting devices etc., The LBMO nanoparticles were prepared by sol–gel auto combustion method. LBMO/P (VDF-TrFE) nanocomposite film was prepared by solution casting method for 0.5% volume fraction of LBMO nanoparticles in P (VDF-TrFE) matrix. This nanocomposite film shows ferromagnetic and ferroelectric properties simultaneously at room temperature. The ME properties of these composite films were studied extensively. The ME coupling coefficient is highly dependent on the angle between ferroelectric polarization and applied magnetic field. The maximum measured in plane ME voltage coefficient $$\left( {\alpha _{{31}}^{V} } \right)$$ is found to be 121.5 mV cm−1 Oe−1with application 25 Oe at 10 kHz by lock-in technique. The $$\alpha _{{31}}^{V}$$ is maximum at the angles 90° and 270° between ferroelectric polarization and applied magnetic field. The hysteresis of $$\alpha _{{31}}^{V}$$ confirms the existence of electric polarized domain formed with the decrease in magnetic field and the process is irreversible.

Magnetoelectric coupling of La0.7Ba0.3MnO3/ poly(vinylidenefluoride-co-trifluoroethylene) nano-composite (0–3) films were studied by varying the volume fraction of La0.7Ba0.3MnO3 in polymer matrix for non-poled and electrically poled conditions. The transverse magnetoelectric coupling coefficient (αV31) value is larger compared to αV33 (logitudinal coupling coeffcient) for composite films. The maximum value of αV31 is found to be 121.44 mVcm−1Oe−1 for poled composite films (0.5% La0.7Ba0.3MnO3 volume fraction) at 10 kHz. These films generate a self-biased voltage 9.1 mV on application of 25Oe alternating magnetic field (Hac). The dependence of αV31 of these films on static magnetic field (Hdc), Hac and frequency is also reported.

The research in developing a single ingredient phosphor for white-light emission is progressively increasing. It is well known that the

Nano-particles of GdFeO3 (GFO) and Gd0.4Sm0.6FeO3 (GSFO) were synthesized by sol-gel auto-combustion method to study the effect of Sm3+doping on physical properties of GFO. Rietveld refinement of x-ray diffraction pattern confirms the proper phase formation of samples and the average octahedral angle of GSFO is found to be 145.54⁰ which is larger compared to GFO 142.53⁰. Temperature dependent DC magnetization measurements showed that Sm doping in GdFeO3introduces spin-reorientation transition which is absent in pure GdFeO3 phase. The dielectric constant of GSFO is found to be larger than that of GFO because of change in hybridization between the O-2p states and Fe-3d states. In both the ceramics at higher temperatures (above 150 °C) conduction mechanism is taking place via oxygen defect charge carrier hoping. The complex impedance analysis revealed that the distribution of relaxation time of charge carriers is temperature independent. Sm doping in GFO not only changed the dielectric properties but also changed the magnetic coercive field and shape of the magnetic isotherm of GFO.

Background & Aims Emricasan, an oral pan-caspase inhibitor, decreased portal pressure in experimental cirrhosis and in an open-label study in patients with cirrhosis and severe portal hypertension, defined as a hepatic venous pressure gradient (HVPG) ≥12 mmHg. We aimed to confirm these results in a placebo-controlled study in patients with non-alcoholic steatohepatitis (NASH)-related cirrhosis. Methods We performed a multicenter double-blinded study, randomizing 263 patients with NASH-related cirrhosis and baseline HVPG ≥12 mmHg to twice daily oral emricasan 5 mg, 25 mg, 50 mg or placebo in a 1:1:1:1 ratio for up to 48 weeks. The primary endpoint was change in HVPG (ΔHVPG) at week 24. Secondary endpoints were changes in biomarkers (aminotransferases, caspases, cytokeratins) and development of liver-related outcomes. Results There were no significant differences in ΔHVPG for any emricasan dose vs. placebo (−0.21, −0.45, −0.58 mmHg, respectively) adjusted for baseline HVPG, compensation status, and non-selective beta-blocker use. Compensated patients (n = 201 [76%]) tended to have a greater decrease in HVPG (emricasan all vs. placebo, p = 0.06), the decrease being greater in those with higher baseline HVPG (p = 0.018), with a significant interaction between baseline HVPG (continuous, p = 0.024; dichotomous at 16 mmHg [median], p = 0.013) and treatment. Biomarkers decreased significantly with emricasan at week 24 but returned to baseline levels by week 48. New or worsening decompensating events (∼10% over median exposure of 337 days), progression in model for end-stage liver disease and Child-Pugh scores, and treatment-emergent adverse events were similar among treatment groups. Conclusions Despite a reduction in biomarkers indicating target engagement, emricasan was not associated with improvement in HVPG or clinical outcomes in patients with NASH-related cirrhosis and severe portal hypertension. Compensated patients with higher baseline HVPG had evidence of a small treatment effect. Emricasan treatment appeared safe and well-tolerated. Lay summary Cirrhosis (scarring of the liver) is the main consequence of non-alcoholic steatohepatitis (NASH). Cirrhosis leads to high pressure in the portal vein which accounts for most of the complications of cirrhosis. Reducing portal pressure is beneficial in patients with cirrhosis. We studied the possibility that emricasan, a drug that improves inflammation and scarring in the liver, would reduce portal pressure in patients with NASH-related cirrhosis and severe portal hypertension. Our results in a large, prospective, double-blind study could not demonstrate a beneficial effect of emricasan in these patients. Clinical Trial Number Clinical Trials.gov #NCT02960204.

We have explored the electric field controlled magnetization in the nanodot CoFe

The existence of magnetostriction in bulk BiFeO3 is still a matter of investigation and it is also an issue to investigate the magnetostriction effect in nano BiFeO3. Present work demonstrates the existence of magnetostrictive strain in superparamagnetic (SPM) BiFeO3 nanoparticles at room temperature and the magnetoelectric (ME) coupling properties in composite form with P(VDF-TrFE). Despite few reports on the magnetostriction effect in bulk BiFeO3 evidenced by the indirect method, the direct method (strain gauge) was employed in this work to examine the magnetostriction of SPM BiFeO3. In addition, a high ME coupling coefficient was observed by the lock-in technique for optimized BiFeO3_P(VDF-TrFE) nanocomposite film. These nanocomposite films also exhibit room-temperature multiferroic properties. These results provide aspects of material with immense potential for practical applications in spintronics and magneto-electronics applications. We report a ME sensor using SPM BiFeO3_P(VDF-TrFE) nanocomposite film for detection of ac magnetic field.

In this study, we investigate magnetoelectric (ME) properties in nanocomposite films (P(VDF-TrFe))/SmFeO3 consist of ferroelectric copolymer, poly(vinylindene fluoride-trifluoroethylene) (P(VDF-TrFe)) and magnetic SmFeO3 nanoparticles. Comparative magnetization vs magnetic field hysteresis loops for un-poled and electric field poled (P(VDF-TrFe))/SmFeO3 nanocomposite films demonstrate strong electric filed control of magnetization. The nanocomposite films exhibit large exchange biasing (EB) effects in magnetic measurements near spin switching temperature (~ 100 K) of SmFeO3 and the EB effects were significantly modified under electric field (E) poled conditions (at E = 200 kV/cm), indicating ME coupling. Remarkably, we observe electric field poling induced self biased converse ME effect in the (P(VDF-TrFe))/SmFeO3 nanocomposite films. The maximum magnetoelectric output voltage (α) obtained is 55 mV/cm/Oe at Hbias = 1 kOe and 25 mV/cm/Oe at Hbias = 0, after electric field poling. The discovery of self biasing phenomenon with converse ME effects at room temperature in flexible (P(VDF-TrFe))/SmFeO3 nanocomposite films is highly desirable for device applications such as electrically controlled thin memory devices and ME sensors etc.

NaNb1−xTaxO3 (x = 0.0, 0.1, 0.2 and 0.3) (NT0, NT1, NT2 and NT3) ceramics are synthesized by conventional solid state reaction technique at high sintering temperature 1150 °C for 4 h. The crystallinity and surface morphology are studied by X - ray diffraction (XRD) and Field emission scanning electron microscopy (FE-SEM) at room temperature, respectively. XRD analysis of Ta ion doped sodium niobate ceramics confirms the formation of single phase with orthorhombic symmetry. In FE - SEM analysis, the effect of tantalum (Ta) ion on the grain growth of NT ceramics is clearly noticeable. With increasing the amount of Ta ion in NT ceramics, size of grains get diminished. The dielectric and impedance behavior of NT material are studied as a function of frequency (100 Hz - 5 MHz) at selected temperature (400 °C - 560 °C). The maximum value of real permittivity ( e ' ) is obtained in NT3 ceramics at 560 °C temperature. The impedance analysis of NT ceramics confirms that the relaxation peaks shift toward higher frequency with a rise in temperature. Such type of change in relaxation peak is attributed to the temperature dependent time relaxation phenomenon present in material.

Disposal of composite materials used vastly in structural applications raises the need to study the reprocessability of these systems for environmental benefits. In this paper, composites of recycled high density polyethylene (R) containing 30 wt.% banana fiber (BF)/7.5 wt.% fly ash cenospheres (FACS) were prepared with 3 wt.% maleic anhydride grafted high density polyethylene (MA-g-HDPE) as a coupling agent using twin screw extrusion followed by injection molding. The effects of thermal cycles (two times extrusion followed by injection molding) were studied on R and its composites. The samples were characterized by using tensile, flexural, izod impact tests, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TGA) and dynamic mechanical analysis (DMA). The tensile and flexural properties were improved by addition of both BF/FACS into the R matrix. The percentage retention in tensile properties of R/BF/FACS(E2) biocomposites (i.e. two times extrusion followed by injection molding) is more than 80 %, while that for flexural properties is more than 90 %. This indicates that R/BF/FACS composites exhibit good retention ability in mechanical properties after subjecting to two times twin-screw extrusion followed by injection molding. DSC results revealed that repeated extrusion improved the crystallization temperature and crystallinity of the composites with a slight reduction in melting temperature. From the TGA results, it was observed that the thermal stability (e.g. Tonset) of R was reduced by the addition of BF/FACS. However, repeated extrusion showed an improvement in thermal stability of the composites.

Multiferroic Y-doped BiFeO3 (BY10FO) thin films were deposited on FTO coated glass substrate using sol-gel spin coating technique. Y-doping causes structural distortion without changing the structure of the parent BiFeO3 (rhombohedral: R3c). The M-H hysteresis curve reveals that the BY10FO film exhibits saturation magnetization at a low-coercive field by suppressing the spiral spin modulated structure. The bipolar resistive switching behavior has been investigated on a Ag/BY10FO/FTO hetero-structure through conventional I-V curve measurements and the device can produce an ON/OFF ratio of around 12 over 30 complete testing cycles. The space charge limited current and Schottky barrier emission conduction mechanism play a crucial role in switching the states between HRS and LRS. The impedance spectroscopy analysis at HRS and LRS confirms the significant degradation of resistance from MΩ to kΩ. The switching mechanism in the hetero-structure is due to migration and recombination of oxygen vacancies present in the film. The non-degradation of the Ag/BY10FO/FTO device after several testing cycles confirms that the switching of resistance between ON and OFF states is reproducible, reversible and controllable to be used for possible future non-volatile resistive random access memory application.

For the first time, effect of tin (Sn) substitution on the structural, ferroelectric, dielectric and piezoelectric properties of lead-free Ba0.98Ca0.02Ti1-xSnxO3 (BCST) compounds with ‘x’ = 0–0.05 mol % was investigated systematically. Room temperature x-ray diffraction (XRD) analysis revealed the tetragonal phase in the composition range 0 ≤ x ≤ 0.03 and co-existence of tetragonal and orthorhombic phases for ‘x’ = 0.05 composition. The experimental density varied between 95 and 97% of the theoretical density. The Curie temperature (TC) exhibited a declining trend from 125 °C to 102 °C with increasing Sn content. The orthorhombic to tetragonal phase transition (TO-T) was observed close to 39 °C for Sn doped compound with ‘x’ = 0.05. Further, the best electrical properties (2Pr ∼16.6 μC/cm2, ɛm ∼ 9063 and d33 ∼ 290 pC/N) were observed for BCST compound doped with ‘x’ = 0.03 proving it an optimal composition among the studied ceramics.

We report the structural and magnetization dynamics of pulsed laser ablated Y3Fe5O12 (YIG) thin films grown on gadolinium gallium garnet (GGG[110]) substrate. The co-planar waveguide ferromagnetic resonance measurement was performed to study the thickness and inhomogeneity effect on damping constant. We also estimated the effective demagnetization ( 4 π M eff ) value which was lower than that of single-crystalline bulk YIG. A detailed line width analysis revealed the significant two-magnon scattering and inhomogeneity contribution to damping which varied for different thickness films. The Gilbert damping constant (α) of the grown film was found to be lowest in the case of 100 nm film (≈3 × 10−4), and the corresponding inhomogeneous broadening (ΔH O) was recorded to be 77 Oe. Further angular measurements on 100 nm thin film revealed the presence of strong uniaxial magnetic anisotropy field of 735 Oe at 10 GHz RF frequency.

Strain mediated magnetoelectric (ME) coupling effect has been investigated in bilayer structure of LSMO/P (VDF-TrFE) nanocomposite in the transverse ME mode. In the transverse mode, Finite Element Method (FEM) based small signal analysis has been performed by the COMSOL Multiphysics 6.0 software. La0.7Sr0.3MnO3(LSMO)/P (VDF-TrFE) nanocomposite (2-2) has been prepared by gluing LSMO pellet with P(VDF-TrFE) polymer film. This bilayer structure shows multiferroic property at room temperature. Simulated FEM modelverifies the magneto-strictive property of LSMO layer and explained the experimental results.Experimental and simulated ME coupling coefficient are found to be very close to each other.

In this work, we have presented a solid-solution of Sm

Traumatic brain injury (TBI) has become a concern in sports, automobile accidents and combat operations. A better understanding of the mechanics leading to a TBI is required to cope with both the short-term life-threatening effects and long-term effects of TBIs, such as the development chronic traumatic encephalopathy (CTE). Kornguth et al., 2017 proposed that an inflammatory and autoimmune process initiated by a water hammer effect at the bases of the sulci of the brain is a mechanism of TBI leading to CTE. A major objective of this study is to investigate whether the water hammer effect is present due to blunt impacts through the use of computational models. Frontal blunt impacts were simulated with 2D finite element models developed to capture the biofidelic geometry of a human head. The models utilized the Arbitrary Lagrangian Eulerian (ALE) method to model a layer of cerebrospinal fluid (CSF) as a deforming fluid allowing for CSF to move in and out of sulci. During the simulated impacts, CSF was not observed to be driven into the sulci during the transient response. However, elevated shear strain levels near the base of the sulci were exhibited. Further, increased shear strain was present when differentiation between white and gray matter was taken into account. Both of the results support clinical observations of Kornguth et al., 2017.

SmFeO3 a member of ReFeO3 (Re stands for rare earth) family has highest spin reorientation temperature (∼ 450 - 480 K) which makes them very useful for Spintronics application. Nano particles of Sm0.3Er0.7FeO3 has been synthesized by sol-gel auto-combustion method to study the effect of Er3+doping on spin reorientation of SmFeO3. Rietveld refinement of the X-ray diffraction pattern revealed that the average octahedral (FeO6) tilting of Sm0.3Er0.7FeO3 ( =18.44□) was increased as compare to SmFeO3 ( =14.42□). TEM image shows the average particle size is of the order of 50-80 nm. Temperature dependent DC magnetization measurement shows, that the Er doping in SmFeO3 resulted in the shifting of its spin reorientation temperature (Tsr) at 140 - 160 K from that of 450 -480 K of SmFeO3. The M-H measurements at 300 K show weak ferromagnetic behavior while paramagnetic behavior at 10 K. Hence, it is shown that by doping of Er in SmFeO3, the Tsr can be modified.

Magnetoelectric coupling of La0.7Ba0.3MnO3/ poly(vinylidenefluoride-co-trifluoroethylene) nano-composite (0-3) films were studied by varying the volume fraction of La0.7Ba0.3MnO3 in polymer matrix for both non-poled and electrically poled conditions. The transverse magnetoelectric coupling-coefficient (αV31) value is larger compared to αV33 (logitudinal coupling-coeffcient) for both non-poled and electrically poled films. Poled composite films are showing highest αV31 = 121.44 mV/Oe-cm at 10 kHz for 0.5% volume fraction of La0.7Ba0.3MnO3. These films generate self-biased voltage 9.1 mV on application of 25Oe alternating magnetic field (Hac). The dependence of αV31 on static magnetic field (Hdc), Hac and frequency for these films is also reported.

The SmFeO3, a family member of rare earth orthoferrite, is a potential candidate for future industrial (spintronics) applications due to highest spin reorientation temperature (453-483 K) among other RFeO3 members. There are ambiguous reports on high permittivity behavior of SmFeO3. In this report, the origin of high permittivity in SmFeO3 is attributed to microstructure rather than inherent material property of material. Ceramic pellets of SmFeO3 were prepared in two different routes i. e. solid-state route and nano-combustion synthesis route. The dielectric and conductivity properties of these pellets were studied as function of frequency as well as temperature. Impedance spectroscopy was used to study the dielectric and resistive behavior of SmFeO3. The central findings of this work are; (i) the high dielectric constant of SmFeO3 is not an inherent material property instead strongly dependent on microstructure and preparation conditions and (ii) the anomalous behavior in dielectric, conductivity and impedance observed at spin reorientation temperature regime of SmFeO3 is attributed to strong magneto dielectric coupling in SmFeO3.

Utilization of magnetoelectric effects in multiferroic materials hold great potential to fabricate nonvolatile memory devices with outstanding characteristics. In particular, organic thin memories are favorable because of their environment friendly nature, mechanical flexibility, and low fabrication cost. In this work, we have demonstrated a room temperature paradigm two level nonvolatile memory operation by exploiting the nonlinear magnetoelectric effects in flexible SmFeO3/P(VDF-TrFE) nanocomposite films using organic ferroelectric polymer (P(VDF-TrFE)) as a host matrix. Strong strain mediated interfacial interactions between ferromagnetic and ferroelectric phases in SmFeO3/P(VDF-TrFE) nanocomposite films allow electric field controlled magnetic switching. The maximum magnetoelectric coefficient (α) obtained is 45 mV cm–1 Oe1– at Hbias= 1 kOe and 16 mV cm–1 Oe1– at Hbias= 0 in electrically poled composite films (30% SmFeO3). The experiments demonstrate that during seven operative cycles for 1500 s, the ...

Pristine and 0.04 wt.% Pr6O11 substituted Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) lead-free ceramics have been synthesized by the conventional solid-state reaction method at 1450 and 1300°C sintering temperatures, respectively. The synthesized compounds were characterized by their structural, microstructural, piezoelectric, dielectric and luminescent properties. Coexistence of tetragonal and orthorhombic phases was observed for both pure and Pr doped BCZT compounds. Higher piezoelectric coefficient (d33) ∼ 220 pC/N, maximum dielectric constant (ɛm) ∼ 4204 and minimum dielectric loss (tanδ) ∼ 0.025 were obtained for Pr doped compound as compared to 180 pC/N, 3353 and 0.034 values, respectively, for the undoped BCZT ceramics. Strong photoluminescence emission spectra consisting of blue (489 nm), green (530 nm) and red (602 nm) light emissions were observed in Pr doped compound. Our results demonstrate that Pr6O11 addition in BCZT ceramics is helpful in increasing the electrical properties, inducing the luminescent effect and simultaneously reducing the sintering temperatures of BCZT. The results have been understood in the light of Pr3+ ions occupying the Ti4+-sites.

The ‘x’ wt% (x = 0, 0.02, 0.04 and 0.06) Pr 6 O 11 modified Ba 0.98 Ca 0.02 Zr 0.02 Ti 0.98 O 3 (BCZT – x Pr) piezoelectric ceramics have been fabricated by the solid state reaction method with sintering at 1450 °C (x = 0) and 1350 °C (0.02 ≤ x ≤ 0.06) for 2 h. The impact of Pr concentration on the structural, microstructural, photoluminescence and ferroelectric properties has been systematically investigated. The x-ray diffraction (XRD) patterns revealed the co-existence of tetragonal and orthorhombic phases at room temperature upto x = 0.04 Pr concentration. The grain size was found to decrease upto x = 0.04 Pr content. Room temperature Raman spectroscopy results were consistent with the XRD results. The photoluminescence (PL) spectra showed significant emissions consisting of strong blue (489 nm), green (528 nm) and red (649 nm) wavelengths. The emission intensities of PL spectrum were strongly Pr concentration dependent and a maximum value was obtained for 0.04 Pr modified BCZT ceramic. Further, a large remnant polarization (2P r ~ 13 µC/cm 2 ) and low coercive field (E C ~ 22 V/cm) were obtained for BCZT – 0.04 Pr ceramic. The crystal structure and microstructure affect the photoluminescence and ferroelectric properties. Such properties of 0.04 Pr modified BCZT ceramic make it the potential candidate for novel integrated and multifunctional devices.

This paper presents the magneto-structural study on orthoferrite TmFeO3 and Sm substituted TmFeO3 across spin reorientation transition (SRT) temperature. A strong change in magnetic anisotropy due to the substitution of the Sm3+was observed, which is reflected as a change in spin reorientation transition (SRT) temperature. The SRT temperature of Tm0.5Sm0.5FeO3is found to be around 200–230 K, which is relatively high in comparison to TmFeO3. A sudden decrease in the value of coercivity has been observed in the SRT region for both the sample. The lattice dynamics of TmFeO3 and Tm0.5Sm0.5FeO3were investigated by temperature-dependent x-ray diffraction and Raman spectroscopy. We observed unusual contractions in the lattice parameter at low temperatures due to complex exchange interaction between RE3+ and Fe3+ ions sub-lattice. Anomalous behavior in lattice parameters was observed in the vicinity of SRT, which confirms the system’s spontaneous magnetostriction.The strong anomaly was observed in line width and phonon frequency of Raman modes of around SRT, which established the spin-lattice coupling in TmFeO3 and Tm0.5Sm0.5FeO3 nanoparticles. Observation of spin-lattice coupling utilizing Raman scattering substantiates our magnetic and structural correlation and supports its candidature for magneto-elastic applications.

Electric-field controlled magnetism is a potential way to realize strong magneto-electric (ME) coupling for nonvolatile memory applications. The electric field induced nonvolatile modulated magnetization was obtained in NiFe2O4/SrRuO3/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) thin film heterostructures. The collective effect of charge and strain significantly modified the magnetization of the NiFe2O4 layer in NiFe2O4/SrRuO3/PMN-PT heterostructures. The analysis of XMCD data establishes that the cation (Fe3+/Ni2+) redistribution occurs on tetrahedral and octahedral sites in the electric field poled NiFe2O4 films, confirming the coupling between magnetism and ferroelectric properties. The films demonstrate repeatable switching of sign of ME output voltage α (α = dP/dH) in response to the applied positive and negative electric pulse, which can be used to store binary information in the nonvolatile manner. The electric-field-controlled switching of α in thin films offers an energy-efficient approach for low-power-consumption nonvolatile memory devices.

In this study, we present first ever fabrication of Er/Dy co-doped Y 2 O 3 transparent ceramic and demonstration of energy transfer upconversion mechanism between Dy 3+ and Er 3+ . The spherical nanoparticles of Er/Dy co-doped Y 2 O 3 were synthesized by coprecipitation technique and transparent ceramics were fabricated by vacuum sintering of nanoparticles at 1750 °C for 5 h. A transmittance of ~ 80% (in ~ 600–2000 nm range) without Fresnel loss correction was achieved by substituting sintering aids like Zirconium and Lanthanum during preparation of nano particles without affecting the cubic phase of Er/Dy co-doped Y 2 O 3 . The upconversion luminescence spectra in visible region have been studied. The measured excitation spectrum gave evidence of the energy transfer from Dy 3+ to Er 3+ energy levels. The Judd–Ofelt intensity parameters, spontaneous emission rate, branching ratios and radiative emission lifetimes corresponding to transition wavelengths of Er 3+ were determined. The observed strong emission band at 564 nm (Er 3+ : 4 S 3/2 → 4 I 15/2 ) under 1077 nm (Dy 3+ : 6 H 15/2 → 6 F 9/2 ) excitation prove its potential as a promising gain medium for compact solid-state upconversion laser.

Controlling the magnetic properties of a material is of great importance for spintronics and magnetoelastic devices. We studied effect of reduced particle size on structural, dielectric and magnetic properties of SmFeO3 nanoparticles prepared by co-precipitation method (SFO-C) and by combustion (SFO-S). Reduced particle size modified interesting magnetic features of SmFeO3. Temperature dependent magnetic study reveal significant enhancement in magnetization reversal temperature and drop in spin reorientation transition temperature. The signature of spin reorientation transition for SFO-C (~ 300 nm) is marked at ~ 450 K, while this temperature drops down to ~ 400 K for SFO-C (~ 50 nm). The magnetization reversal temperature is achieved at 30.5 K for SFO-C, much higher than 4 K, reported for the single crystal and bulk SmFeO3. The presence significant anomalies in the temperature dependent dielectric behavior of SmFeO3 samples across spin reorientation transition temperature indicate magneto electrical coupling. Strong exchange–bias effect is observed at low temperature for both the samples. The lowering of spin reorientation/switching transition temperature due to reduction in particle size and the signature of magnetoelectric coupling at this temperature are useful for room temperature devices. The observed experimental results establish that the spin switching properties of SmFeO3 can be modified for practical applications in devices.

Objectives: To make molecular identification of Arthrobacter sp., an actinomycetes isolated from the rhizospheric region of Bhitarkanika mangrove forest and production optimization for the enhanced antimicrobial bioactive metabolite produced by the isolate. Methods: Submerged fermentation by shake flask method in starch casein broth was employed to optimize the environmental and nutritional parameters. Agar well diffusion method was employed to study the effect of different environmental parameters such as incubation period, pH, temperature, salt concentration, and influence of various nutrients (carbon and nitrogen sources) on antimicrobial metabolite production. Findings: The 16S rDNA sequence was analyzed using BLAST of NCBI data base and found to be a member of Arthrobacter sp., an actinomycete and named as Arthrobacter sp. SAS16. Again, the sequence was deposited in NCBI Genbank under the Accession Number KR401260. The production of the antimicrobial metabolite was maximum at eight days of incubation at 30oC in alkaline medium (pH 8.0) using glycerol (1%), casein (0.5%) as carbon and nitrogen source respectively in presence of 2% sodium chloride. Application/Improvements: The isolate Arthrobacter sp. SAS16 isolated from Bhitarkanika mangrove forest, Odisha, India, possesses remarkable potential as a source of novel antimicrobial metabolites. Further, chemical and structural characterization of the antimicrobial metabolites produced by the actinomycetes is highly essential. Keywords: Antimicrobial, Arthrobacter sp., Mangrove, Optimization

We report the fabrication of transparent (Yb0.01Zr0.02La0.01Y0.96)2O3 ceramic pellets by vacuum sintering of non-agglomerated spherical nanoparticles which were prepared by co-precipitation method. The co-doping of La3+ and Zr4+ in Yb:Y2O3 enhanced the transparency of sintered ceramic pellet. The inline transparency of (Yb0.01Zr0.02La0.01Y0.96)2O3 ceramic pellets improved to ~80% at lasing wavelength (1030 nm) which is comparable to theoretical transmittance for Y2O3 (without Fresnel correction). The dopants in Yb:Y2O3 did not change the spherical nature of nanoparticles but changed the particle size distribution. The cross-sectional SEM images confirmed the effect of dopant on reduction of pores and merger of grains of La3+ and Zr4+ doped transparent Yb:Y2O3 ceramic pellet. The dopants didn’t affect the emission and absorption wavelength of transparent Yb:Y2O3 ceramic pellet. The absorption cross section at 906, 951 and 976 nm excitations are found to be 1.97 × 10−20, 2.27 × 10−20 and 3.59 × 10−20 cm2 respectively.

Rapid formation of stable silver nanoparticles (Ag-NPs) was observed on exposure of the aqueous extract of Donax cuneatus body tissue to 1 mM AgNO3 solution. UV–visible spectrum showed a broad band at 450 nm wavelength, confirming for plasmon resonance line of Ag metallic nanoparticles. Size of synthesized Ag-NPs ranged between 5 and 50 nm. These Ag-NPs showed a significant antimicrobial effect against deadly human pathogens like Klebsiella pneumoniae and Escherichia coli.

Nanophosphors of (Sr0.98-x Mgx Eu0.02 )2 SiO4 (x = 0, 0.18, 0.38, 0.58 and 0.78) were prepared through low temperature solution combustion method and their luminescence properties were studied. The emission peak for Eu2+ -doped Sr2 SiO4 nanophosphor is observed at ~490 nm and ~553 nm corresponding to two Sr2+ sites Sr(I) and Sr(II) respectively for 395 nm excitation. However the addition of Mg2+ dopant in Sr2 SiO4 leads to suppression of ~553 nm emission peak due to absence of energy levels of Sr (II) sites which results in a single broad emission at ~460 nm. It was shown that the emission peak blue shifted with increase in Mg concentration which may be attributed to change in crystal field environment around Sr(I) sites. Therefore, the (Mg0.78 Sr0.20 Eu0.02 )2 SiO4 nanophosphor can be used for blue emission and the Sr2 SiO4 :Eu0.042+ for green-yellow emission at 395 nm excitations. The Commission International de L'Eclairage (CIE) chromaticity coordinates for mixed powders of (Mg0.78 Sr0.20 Eu0.02 )2 SiO4 and Sr2 SiO4 :Eu0.042+ (in a 1:1 ratio) fall in the white region demonstrating the possible use of the mixture in white light generation using near-UV excitation source.

Tb 3+ /Yb 3+ co-doped Y 2 O 3 transparent ceramics were fabricated by vacuum sintering of the pellets (prepared from nanopowders by uniaxial pressing) at 1750 °C for 5 h. Zr 4+ and La 3+ ions were incorporated in Tb 3+ /Yb 3+ co-doped Y 2 O 3 nanoparticle to reduce the formation of pores which limits the transparency of ceramic. An optical transmittance of ∼80% was achieved in ∼450 to 2000 nm range for 1 mm thick pellet which is very close to the theoretical value by taking account of Fresnel’s correction. High intensity luminescence peak at 543 nm (green) was observed in these transparent ceramics under 976 and 929 nm excitations due to Yb–Tb energy transfer upconversion.

The optimization of dopant concentration in upconverting nanophosphor is a real problem because of distinct limits defined by surface quenching, energy transfer and cross relaxation phenomenon. In this work, LaF3 based nanophosphors with different doping concentration of Yb3+ and Tb3+ ions were prepared by coprecipitation route. Particles are formed in spherical shape with narrow size distribution i.e. in ∼50–80 nm range. The volume of LaF3 unit cell shrinks with the doping of Tb3+ and Yb3+, whereas no variation in its phase were observed. The nanophosphors exhibit characteristics of dual mode spectral emitter. Thus, irrespective of excitation source (i.e. either UV or NIR), the intense green emission at 541 nm was observed. The material LaF3 with optimized molar doping concentration of 5%Tb3+ and 10%Yb3+ shows intense green emission on excitation with either UV or IR light. The time resolve luminescence emission were studied to explore the probability of involved energy transfer process between two dopant ions.

MgFe2O4 (MFO) and (Ba0·85Ca0.15) (Zr0·1Ti0.9)O3 (BCZT) was prepared by solid state route and are found to be ferromagnetic and ferroelectric at room temperature respectively. MFO/BCZT composite (50:50 M concentration of MFO and BCZT) was also prepared by solid state route. Multiferroic properties of MFO/BCZT ceramic composite were investigated. Scanning electron micrograph confirms the distribution of small grains of MFO around large grain of BCZT for proper surface interaction. MFO/BCZT composite exhibits saturated magnetization of 12 emu/gm, which reduce to 10 emu/gm on electrical poling at 2.5 kV/cm indicating magneto-electric coupling between MFO and BCZT through interface interaction. The composite also exhibits proper ferroelectric polarization, which is confirmed from I–V characteristic plot (occurrence of double minima as that of proper ferroelectric). The transverse magnetoelectric coupling coefficient (αV31) for this composite is found to be 7.97 mVcm−1Oe−1 at 10 kHz. MFO/BCZT ceramic composite exhibit multiferroic and magnetoelectric coupling properties for 50:50 M concentration at room temperature may be suitable for device applications.