• ARVIND KUMAR

Articles written in Bulletin of Materials Science

• Effect of metalloids on crystallization and magnetic behaviour of FeCoSiB based metallic glass

A series of amorphous iron–cobalt alloys with varying metalloid, boron and silicon contents were studied for their thermal stability and magnetic behaviour. The crystallization temperature and thermal stability increased with the silicon content. Good soft magnetic properties were observed for the materials with nominal composition, (Fe0.79Co0.21)77Si12.2B10.8. The magnetic properties were further improved by annealing.

• Study on thermodynamic, electronic and magnetic properties of RE$_2$Cu$_2$Cd (RE $=$ Dy $−$Tm) intermetallics: first-principle calculation

RE$_2$Cu$_2$Cd (RE $=$ heavy rare earth elements: Dy, Ho, Er, Tm) intermetallics show the interesting physical, magnetic and chemical properties with reference to magnetocaloric effect. To explore the relevant complex performance of RE$_2$Cu$_2$Cd materials, which crystallizes in Mo$_2$B$_2$Fe-type structure with space group P4/$mbm$; electronic, magnetic and thermodynamic properties have been studied using first principle theory. Electronic properties, i.e. spin-polarized electron dispersion curves (band structure) and density of state calculations showthat (Dy/Ho/Er/Tm)$_2$Cu$_2$Cd compounds aremetallic with dominant character of Dy-f spin down channels. Whereas magnetic and electron spin-polarization calculations show that studied materials behave like metallic ferromagnet having nearly fully spin-polarized characteristics. The effect of temperature on bulk modulus, $B$, volume of unit cell, $V$, entropy, $S$ and specific heat, $C_{\rm v}$ has also been studied using quasi-harmonic Debye model.

• Structural, dielectric and magnetoelectric coupling analysis in SrBi$_2$Nb$_2$O$_9$–CoFe$_2$O$_4$ composites

Ferroelectric–magnetic composites of SrBi$_2$Nb$_2$O$_9$–CoFe$_2$O$_4$ (SBN–CFO) were synthesized via conventional solid state reaction route. The powder X-ray diffraction, Raman spectroscopy and scanning electron microscopy measurements confirm the existence of two chemically separated phases and phase purity in the SBN–CFO composites. Magnetization measurements confirm the enhanced values of the magnetic parameters. The change in the area of theferroelectric P vs. E loops with frequency confirms the enhanced ferroelectric nature of the SBN–CFO composites. The quantified maximum values of magnetoelectric coefficient ($\alpha$) are observed from the $P$ vs. $E$ loop measurements in the influence of applied magnetic field and found to be 4.475 mV cm$^{-1}$ Oe$^{-1}$ at 688 Oe for SBN–0.1CFO and 3.389 mV cm$^{-1}$ Oe$^{-1}$ at 1000 Oe for SBN–0.2CFO composites, respectively. The shifting in the peaks of temperature-dependent dielectric maxima towards the higher temperature side confirms the relaxor behaviour in the SBN–CFO composite samples.

• # 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