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Manas Kumar Dalai

Publications and source records attributed to Manas Kumar Dalai.

2 recordsLinked to original sources

Discovery of Graphene Sheets and C-Rich Micro-Oval structure in Stingless Bee Hive; Leading to an Emergent Material with Debut of Blue Emission

Naturally produced stingless bee hive (NP-SBH) is an intricately produced material by the combination of waxes, resin and other biological materials that offers protection and structural stability to the bee colony. This study explores a detailed analysis of Indian stingless bee hive material using multi-characterization techniques approach to evaluate their morphological, ultrastructural, chemical composition and their crystallinity. FESEM reveal uniformly distributed micro-oval structures along with graphene sheets throughout the observed region. Furthermore, Energy Dispersive X-ray Analysis (EDAX) provides the richness of carbon (C) in graphene as well as in the micro-oval structure. HRTEM gives an insight about the internal ultrastructure and arrangement of atoms in the sample which revealed the presence of multiple graphene sheets. The ring shape electron diffraction pattern and high resolution lattice fringes provide the arrangement of carbon atoms, with interlayer spacing (d) value 3.4 Å, well agreed with that of graphene. Furthermore, X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy support the presence of graphene. As a debut, we observe blue emission from PL spectroscopy with decay times 1.18 ns (42 %) and 5.41 ns (58 %).

cond-mat.mtrl-sci

Superconductivity in Ag implanted Au thin film

Au and Ag are known to be metallic and none of them have shown independently superconductivity. Here we show superconductivity in Ag implanted Au thin films. Ag implanted Au films of different thicknesses have been studied using four probe resistance versus temperature measurements. We have also measured the pristine samples (i.e. without any implantation) to compare the transport properties. The superconducting transition occurs around ~2 K (TC) for Ag implanted 20 nm Au film (the lowest resistance observed below TC is ~10-6 Ohm). Change of Tc towards lower temperatures has been observed under the effect of increasing current and magnetic field which endorses the superconducting state. Further the V~I measurements were carried out to verify the superconducting nature. On the other hand, the pristine samples clearly did not exhibit superconductivity down to 1.6 K. Our results open an avenue for further exploring this type of novel superconductivity for future applications.

cond-mat.supr-con