• H K POSWAL

Articles written in Bulletin of Materials Science

• Probing bipyramid microstructure of pure and Dy-doped HoMnO$_3$ using high pressure and low temperature studies

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.

• # Bulletin of Materials Science

Volume 46, 2023
All articles
Continuous Article Publishing mode

• # 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

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Posted on July 25, 2019

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