• NANDAKUMAR KALARIKKAL

Articles written in Bulletin of Materials Science

• Composition-dependent structural, electrical, magnetic and magnetoelectric properties of $(1-x)$BaTiO$_3$$-xCoFe_2O_4 particulate composites Multiferroic composite with the general formula (1 - x)BaTiO_3$$-x$CoFe$_2$O$_4$ ($x = 0.05$, 0.15, 0.25, 0.35 and0.45) has been synthesized by a standard solid-state reaction route. Powder X-ray diffraction analysis confirms the existence of ferrite (spinel CoFe$_2$O$_4$) and ferroelectric (tetragonal BaTiO$_3$) biphase without any impurity phases in the sintered composites. Microstructure of the composite displays two different grain sizes and shapes studied from SEM analysis. The composites show both ferroelectric and ferromagnetic ordering: the saturation magnetization ($M_{\rm s}$) and retentivity ($M_{\rm r}$) of the composite are improved with the increase in ferrite phase, while leakage current, ferroelectric and dielectric properties of the composites show a drop. Existence of coupling between ferroelectric and ferromagnetic ordering measured through magnetodielectric (MD) and magnetoelectric (ME) studies reveal an increase in % MD and ME coefficients with an increase in ferrite content. An enhanced ME coupling coefficient of 17 mV cm$^{-1}$ Oe$^{-1}$ has been realized at a dc magnetic field of 5 kOe with a ac frequency of 50 Hz in $(1 - x)$BaTiO$_3$$-x$CoFe$_2$O$_4$ ($x = 0.45$) composite.

• Laponite$^{\circledR}$clay/poly(ethylene oxide) gel beads for delivery of plant growth-promoting rhizobacteria

Hydrogels have been extensively used for crop improvement and this study presents a novel and facile synthesis method of clay nanocomposite hydrogel beads for encapsulation of plant probiotic bacteria. The nanocomposite used in the study consists of poly(ethylene oxide) and laponite clay. The hydrogel beads were prepared in a one-step synthesis technique to encapsulate five Pseudomonas strains both alone and as a consortium. The effects of this polymer nanocomposite (PNC) gel/plant growth-promoting rhizobacteria (PGPR) in various combinations were studied using Vigna unguiculata by evaluating its growth parameters. Here, significant improvement of leaf length, leaf number andshoot length could be observed for the consortium-encapsulated PNC hydrogel beads treated plants when compared with the untreated as well as single strain bacteria treated. In addition, the microbial viability studies indicated the PGPR to be stable up to 60 days within the PNC beads. The results of the study indicate great potential of the PNC beads mediated delivery of plant probiotic bacteria for the replacement of chemically synthesised and environmentally hazardous fertilisers.

• Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020