• Fulltext


        Click here to view fulltext PDF

      Permanent link:

    • Keywords


      Multiferroics; low temperature; infrared spectroscopy; phonons; manganites; high pressure XRD.

    • Abstract


      Bipyramidal distortions play the governing role in physical properties of HoMnO$_3$ multiferroics. We have carried out angle-dispersive high pressure synchrotron X-ray diffraction experiments on hexagonal HoMnO$_3$ to find the evolution of bipyramidal parameters upon external compression. It is found that the average bond-lengths and bond-angles between Mn and O atoms depict significant reduction, which results in the distortion in MnO$_5$ bipyramidal structure athigh pressures. Further, since subtle variations in these distortions are used to compare the properties of hexagonal HoMnO$_3$ manganite series, in-situ low temperature infrared spectroscopic studies of 10% Dy-doped HoMnO$_3$ have beencarried out to study the effect of further increase in R-site cationic radius on MnO$_5$ deformations. It is found that the phonon modes specifically related to the motion of Mn and O atoms in ab-plane display irregularities near magnetic transition temperatures ($T_N$ and T$_{SR}$) via spin phonon coupling. Even a small increase in average ionic radius of rare-earth atom suppresses this anomalous behaviour and follows the trend of undoped hexagonal rare-earth manganites.

    • Author Affiliations



      1. High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
    • Dates

  • 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

© 2022-2023 Indian Academy of Sciences, Bengaluru.