• A K Rastogi

      Articles written in Bulletin of Materials Science

    • Phase transitions in molybdenum sesquisulphide systems between 80 and 600 K

      A K Rastogi R K Ray

      More Details Abstract Fulltext PDF

      Samples of Mo2S3 system and substituted derivatives with Cr, Nb, Cu and Mn have been studied. The resistivity, thermoelectric power, magnetic susceptibility and specific heat indicate clear phase transition at temperatures between 200 and 310 K. X-ray investigations establish the transitions at these temperatures as structural changes. Careful analysis of the data helps to obtain working values for a model for the energy band. Carrier density, effective mass, mobility, band overlap parameter, density of states for the electrons and holes in the overlapping bands at the Fermi level and the band gap for a higher conduction band are obtained.

    • Evidence for the complicated Fermi surface in 2H- and 4H-NbSe$_2$


      More Details Abstract Fulltext PDF

      In this study, we have found superconducting state (SC) at 7.4 and 6.4 K and charge density wave state (CDW) at 35 and 42 K in our 2H- and 4H-NbSe$_2$ single crystals, respectively. Besides this, there exists a positive magneto-resistance (MR) below the CDWtransition temperature on both the crystals. Therefore, we have calculated their fractional change in MR i.e., $\Delta \rho/\rho_0$ around 8 K in $H_{\perp}$ plane of NbSe$_2$ and $H_{\parallel}$ plane of NbSe$_2$ configurations. Both single crystals show anisotropic $\Delta \rho/\rho_0$, which are described by Kohler’s rule, two-band model and magnetic breakdown model. In the present scenario, the magnetic breakdown model explains our anisotropic $\Delta \rho/\rho_0$ better than other two models: Kohler’s and two-band model. This model also established the presence of complicated Fermi surface on both single crystals.

  • Bulletin of Materials Science | News

    • 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

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.