• R Jagannathan

      Articles written in Bulletin of Materials Science

    • A mössbauer study of hyperfine interactions in the boroferrite Fe3−xGaxBO6(x=0, 0·12)

      M Vithal R Jagannathan N Ravi

      More Details Abstract Fulltext PDF

      Fe3BO6 shows no thermal hysteresis around the phase transition temperatureTSR=418 K; Fe2·88Ga0·12BO6 undergoes spin transition atTSR=403 K resulting in a reduction of theTSR. Both these features are different from the reported observations on α-Fe2O3. The two Fe3+ sites show difference in their magnetic interactions. Ga3+ replaces Fe3+ in a random manner.

    • Spin-wave excitations in amorphous ferromagnets

      Anil K Bhatnagar B Bhanu Prasad N Ravi R Jagannathan

      More Details Abstract Fulltext PDF

      Mössbauer measurements have been performed on a number of metallic glasses. The temperature dependence of average hyperfine or internal magnetic fieldHeff(T) arises from long wavelength spin wave excitations in these glasses. Values ofB3/2 andC5/2 are in general much higher than those observed for crystalline ferromagnets indicating higher density of states for spin waves in amorphous ferromagnets.

    • Rare earth fluorescence in NASICON type phosphate glass, Na3TiZnP3O12

      G Vijaya Prakash P Nachimuthu M Vithal R Jagannathan

      More Details Abstract Fulltext PDF

      The emission spectra of Pr3+, Eu3+ and Dy3+ doped in NASICON type phosphate glass, Na3TiZnP3O12 (NTZP) are studied. The dopant rare earth ions occupy sites with 8–9 coordination in a highly covalent environment. For Pr3+ ion, calculated and observed branching ratios for lasing transitions3P03H4,6 agree well and found to be 0·64 and 0·24, respectively. The emissions of Pr3+ show strong temperature dependence on account of Boltzmann population of the higher excited states at room temperature. The excitation spectrum of Eu3+ gives rise to phonon assisted side band for5D27F0 transition at higher energy side with a phonon energy maximum of 1022 cm−1 and an electron phonon coupling strength (g) of 0·018. The value of phonon energy maximum agrees with infrared spectral data. The results show that observation of high energy emissions in phosphate glasses require much higherg values. The red/orange and yellow/blue transitions of Eu3+ and Dy3+, respectively show that the Eu3+ occupy more distorted site than Dy3+.

  • 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.