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We report an enhanced magnetoelectric (ME) effect in spin–phonon coupled single-phase La1−xSmxYFe2O6 (0 ≤ x ≤ 1). The structural, electric, magnetic, and ME properties have been investigated to establish their interplay leading to magnetoelectricity. X-ray diffraction study suggests the facilitation of the P21nm phase (double perovskite lattice arrangements) formation and improved structural order due to the substitution of Sm in the lattice. Antiferromagnetic (AFM) transition ∼700 K along with a spin-reorientation transition around room temperature (RT) and below is observed in the thermomagnetic curve. The indication of short range ordering in the magnetization data in the form of a non-Griffiths-like phase (nGP) is observed. The short range ordering could be minimized along with consequent improvement in AFM ordering, due to Sm substitution. An enhanced (∼31% with respect to x = 0) RT first-order ME coupling coefficient ∼0.59 mV cm−1 Oe−1 in x = 0.75 composition is observed. The findings reported here open the door to exercise spin-reorientation transition in the spin–phonon coupled double perovskites for spintronic device applications. [ABSTRACT FROM AUTHOR]

We report an enhanced magnetoelectric (ME) effect in spin–phonon coupled single-phase La1−xSmxYFe2O6 (0 ≤ x ≤ 1). The structural, electric, magnetic, and ME properties have been investigated to establish their interplay leading to magnetoelectricity. X-ray diffraction study suggests the facilitation of the P21nm phase (double perovskite lattice arrangements) formation and improved structural order due to the substitution of Sm in the lattice. Antiferromagnetic (AFM) transition ∼700 K along with a spin-reorientation transition around room temperature (RT) and below is observed in the thermomagnetic curve. The indication of short range ordering in the magnetization data in the form of a non-Griffiths-like phase (nGP) is observed. The short range ordering could be minimized along with consequent improvement in AFM ordering, due to Sm substitution. An enhanced (∼31% with respect to x = 0) RT first-order ME coupling coefficient ∼0.59 mV cm−1 Oe−1 in x = 0.75 composition is observed. The findings reported here open the door to exercise spin-reorientation transition in the spin–phonon coupled double perovskites for spintronic device applications. [ABSTRACT FROM AUTHOR]

This work reports the simultaneous observation of converse magnetoelectric (CME) and direct magnetoelectric (DME) effects in LaYFe2O6. The structural, magnetic, and magnetoelectric properties of LaYFe2O6, prepared by the sol-gel auto-combustion method and sintered at various temperatures, have been studied. The x-ray powder diffraction study suggests the double perovskite structure with symmetries P21nm (∼90%) and Pbnm (∼10%). The alternate ordering of La and Y ions is confirmed by the neutron powder diffraction (ND) study, which also suggests the antiferromagnetic (AFM) ordering of spins. AFM behavior is also manifested by the magnetic field-dependent magnetization (M) measurement. A higher P21nm phase content is desirable in the context of magnetoelectricity. Magnetic transition (∼700 K) is asserted in the temperature-dependent M measurement. The isothermal magnetization study shows weak ferromagnetism probably due to gradually increasing spin canting with temperature until the transition temperature. The highest CME coefficient (∼2.26 mOe cm/V) as well as DME coefficient (∼0.45 mV/cm Oe) in this material are recorded. True magnetoelectricity for temperature as high as 400 K opens up a new avenue on the playground of magnetoelectric (ME)-based applications. [ABSTRACT FROM AUTHOR]

This work reports the simultaneous observation of converse magnetoelectric (CME) and direct magnetoelectric (DME) effects in LaYFe2O6. The structural, magnetic, and magnetoelectric properties of LaYFe2O6, prepared by the sol-gel auto-combustion method and sintered at various temperatures, have been studied. The x-ray powder diffraction study suggests the double perovskite structure with symmetries P21nm (∼90%) and Pbnm (∼10%). The alternate ordering of La and Y ions is confirmed by the neutron powder diffraction (ND) study, which also suggests the antiferromagnetic (AFM) ordering of spins. AFM behavior is also manifested by the magnetic field-dependent magnetization (M) measurement. A higher P21nm phase content is desirable in the context of magnetoelectricity. Magnetic transition (∼700 K) is asserted in the temperature-dependent M measurement. The isothermal magnetization study shows weak ferromagnetism probably due to gradually increasing spin canting with temperature until the transition temperature. The highest CME coefficient (∼2.26 mOe cm/V) as well as DME coefficient (∼0.45 mV/cm Oe) in this material are recorded. True magnetoelectricity for temperature as high as 400 K opens up a new avenue on the playground of magnetoelectric (ME)-based applications. [ABSTRACT FROM AUTHOR]

Herein, we report a fundamental study revealing the substantial change in magnetic and electrical properties promoted by manganese (Mn) substitution in the iron (Fe) site of double perovskite LaYFe2O6 [LaYFe2-xMnxO6; x = 0, 0.05, 0.10, and 0.15], which is prepared by the sol–gel auto-combustion method. The structural, morphological, magnetic, and electrical properties of all the samples are investigated to explore the influence of Mn in the compound. X-ray diffraction (XRD) study reveals the confirmation of phase formation with orthorhombic crystal structure having symmetries P21nm and Pbnm (small contribution). X-ray photoelectron spectroscopy (XPS) analysis corroborates the mixed valence state of Fe and Mn, while the dominancy of + 3 oxidation state can be confirmed for them. Magnetization study reveals that the transition temperature reduces drastically (~ 100 K) by the Mn substitution and approaches toward room temperature (RT). At 573 K, the maximum magnetization value enhanced up to ~ 30% by the Mn substitution. Grain boundary contribution in the electrical response is more prominent in the higher Mn content samples. The application of DC magnetic field exhibits a significant influence on the impedance spectra due to the substitution of Mn in the lattice, which corroborates the signature of magnetoelectric (ME) coupling. The presence of ME coupling is further confirmed by the direct magnetoelectric measurement. This finding along with the above RT magnetic transition could make it a feasible candidate for ME-based applications. [ABSTRACT FROM AUTHOR]

This work represents an effective approach to witness the true impedance profiles of the material. Here, a double-perovskite material LaYFe2O6 is prepared by the sol–gel auto-combustion method, which is characterized by the x-ray diffraction (XRD), field emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA)–differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS) technique. The XRD measurement confirms the successful synthesis of the said material with orthorhombic crystal structure having symmetry P21nm (~ 90%) and a slight contribution from Pbnm phase (~ 10%). The FESEM image suggests porous nature of the sample having grain size ~ 150 nm, sintered at 1473 K. TGA with simultaneous DSC measurement shows slight but gradual mass loss (related to adsorbed gases/vapors) above 400 K. The EIS shows influence of the adsorbed gases/vapors in the pores of the pellet on the impedance data. In this context, a homemade open-atmospheric impedance measurement setup is developed. The EIS measurement are done for (1) as-prepared sample, (2) sample preheated to 473 K before performing EIS, and (3) sample preheated to 400 K under vacuum. The process giving best result (having minimum effect of the adsorbed gases on the observed impedance spectra) is found by following the method (2). [ABSTRACT FROM AUTHOR]

Banana is an important commercially available natural fibre, suitable for making coarse yarns. It has also potential for making fine home and apparel textiles after requisite chemical intervention or blending with other fine fibres. For making such products, chemical processing, namely bleaching, coloration and finishing, play an important role. Bleaching of fibre is generally carried out in highly alkaline condition and at high temperature of 85°C using hydrogen peroxide to achieve whiteness index of > 70 with about 25% loss in tensile strength. To achieve a similar whiteness index, while addressing strength loss, a fibre friendly low‐temperature low‐alkali based peracetic acid (PAA) bleaching of banana fibre has been proposed in the present article. Important bleaching process parameters, namely PAA concentration (10–30 g/L), time (60–180 min) and temperature (60–80°C), have been varied for optimisation of the bleaching process. Banana fibre bleaching using PAA concentration of 20 g/L at 70°C for 2 h can produce fibre with whiteness index of > 70, which is suitable for subsequent coloration. The PAA bleached banana fibre can retain 84% of its bundle strength and 95.6% of its weight. Physical (strength, fineness), chemical (attenuated total reflectance Fourier‐transform infrared [ATR‐FTIR], energy dispersive X‐ray spectroscopy [EDX]), optical (colour) and morphological (scanning electron microscopy [SEM]) properties of banana fibres before and after bleaching were evaluated to study the efficacy of the process. [ABSTRACT FROM AUTHOR]

To eliminate the demerits of irreversibility associated with a gas-sensing material, it is always indispensable to know the exact origin of the same. In this view, the present study associates a perovskite to investigate the origin of irreversible sensing by a non-conventional bismuth ferrite (BiFeO3) nanomaterial prepared by a simple solgel technique. Yttrium (Y) doping in BiFeO3 significantly enhances the response performance and eliminates the irreversible nature, showing a reversible-type sensing behavior for selective detection of acetone (cross selectivity, Rcross = RAcetone/Rxylene: 20) along with the virtue of very low sensing ability (1 ppm), long-term stability with a negligible deviation in response value (R = 3.5 ± 0.25) toward 5 ppm acetone tested repeatedly for 300 days, and excellent repeatable over nine loops character desirable for practical application of the perovskite material. A remarkably highest response (R = ΔG/Ga) of 52 was achieved toward acetone utilizing Y-doped BiFeO3 perovskite. A possibility of the formation of closed pores and incomplete desorption of the reducing species (volatile organic compounds) from the active sites of the sensor has been considered the prime origin of unfinished recovery. Finally, irreversible to reversible transition in sensing has correlated with the structural and morphological change resulting from the substitution of the Bi3+ ion by the Y3+ ion, particularly at the A-site of the perovskite BiFeO3 due to Y-doping. [ABSTRACT FROM AUTHOR]