Browsing by Author "Chakingal, Nithya"

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    Friction of magnetene, a non–van der Waals 2D material
    (AAAS, 2021) Serles, Peter; Arif, Taib; Puthirath, Anand B.; Yadav, Shwetank; Wang, Guorui; Cui, Teng; Balan, Aravind Puthirath; Yadav, Thakur Prasad; Thibeorchews, Prasankumar; Chakingal, Nithya; Costin, Gelu; Singh, Chandra Veer; Ajayan, Pulickel M.; Filleter, Tobin
    Two-dimensional (2D) materials are known to have low-friction interfaces by reducing the energy dissipated by sliding contacts. While this is often attributed to van der Waals (vdW) bonding of 2D materials, nanoscale and quantum confinement effects can also act to modify the atomic interactions of a 2D material, producing unique interfacial properties. Here, we demonstrate the low-friction behavior of magnetene, a non-vdW 2D material obtained via the exfoliation of magnetite, showing statistically similar friction to benchmark vdW 2D materials. We find that this low friction is due to 2D confinement effects of minimized potential energy surface corrugation, lowered valence states reducing surface adsorbates, and forbidden low-damping phonon modes, all of which contribute to producing a low-friction 2D material.
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    Magneto-structural phase transition in exfoliated pyrrhotite (Fe7S8) ultra-thin sheets
    (Oxford University Press, 2023) Puthirath Balan, Aravind; Oliveira, Eliezer F; Costin, Gelu; Gray, Tia; Chakingal, Nithya; Biswas, Abhijit; Puthirath, Anand B
    Non-van der Waals (n-vdW) 2D materials are gaining popularity due to their exciting confinement-enhanced properties for magnetic, catalytic and optoelectronic applications. The recent discovery of mechanical and liquid exfoliation of n-vdW materials along the cleavage planes, owing to the very low scission energies, is encouraging and opens the avenue for further exploration of n-vdW materials having exceptional properties. Herein, we successfully isolated a few layers of pyrrhotite (Fe7S8) nanosheets from bulk mineral ore by means of liquid phase exfoliation in organic solvent and studied the magnetic ordering at bulk and exfoliated samples. Both experimental and first principle theoretical investigations point out confinement-induced magneto-structural phase transition from ferromagnetic monoclinic (4M) to antiferromagnetic hexagonal (3T) characterized by the suppression of Besnus transition.