Dr Jan Pokorný

BSc, MSc, PhD
Research Associate

Address:
Department of Materials Science and Engineering
Sir Robert Hadfield Building
Mappin Street, Sheffield, S1 3JD

Telephone: +44 (0) 114 222 5504
Fax: +44 (0) 114 222 5943

Email: j.pokorny@Sheffield.ac.uk

Jan Pokorny obtained his MSc in Physics from Charles University in Prague, Czech Republic in 1992. Since 1993 he has been employed by The Institute of Physics, Academy of Sciences of the Czech Republic. In 2007 he obtained his PhD on "Raman spectroscopy on selected ferroelectric perovskite materials” from Czech Technical University in Prague. In February 2008 he took up a three-year PDRA position at The University of Sheffield, while being on sabbatical leave from the Institute of Physics. Since February 2011 he has been simultaneously employed by The University of Sheffield (60 %) and the Institute of Physics in Prague (40 %).

Research interests

My research interests cover lattice dynamics, phase transitions and related phenomena in dielectrics. I am studying properties of both “classical” and “hot topic” functional materials, including pure and doped BaTiO₃ ceramics, BiFeO₃-based multiferroic ceramics and films, high-temperature dielectrics as well as environmentally friendly lead-free perovskites and tungsten-bronze structures.

Current research and responsibilities

As a Raman facility coordinator, I have the following responsibilities:

• Management of the micro-Raman Laboratory.
• Maintenance and performance enhancements of the Raman instrumentation.
• Training in use of the Raman spectrometer and data analysis, including numerical data processing.
• Creating in-house software for data processing and analysis.

In collaboration with the Institute of Physics in Prague, I participated in developing a novel technique to reconstruct anisotropic crystal properties from a large set of independent local measurements on a macroscopically isotropic ceramic sample. The novel approach combines spatial resolution of current micro-Raman spectrometers, ab-initio calculations and numerical treatment (curve-fitting) of a large set of spectra. The new method was used for conclusive identification of pure zone-center polar modes in BiFeO₃.

Key publications

• J. Pokorny, U. M. Pasha, L. Ben, O. P. Thakur, D. C. Sinclair and I. M. Reaney: Use of Raman spectroscopy to determine the site occupancy of dopants in BaTiO₃, J. Appl. Phys. 109(11) 114110 (2011). DOI: 10.1063/1.3592192.
• J. Hlinka, J. Pokorny, S. Karimi and I. M. Reaney: Angular dispersion of oblique phonon modes by Raman scattering in BiFeO₃, Phys. Rev. B 83(2), 020101 (2011). DOI: 10.1103/PhysRevB.83.020101.
• S. Karimi, I. M. Reaney, Y. Han, J. Pokorny and I. Sterianou: Crystal chemistry and domain structure of rare-earth doped BiFeO₃ ceramics, J. Mater. Sci. 44(19), 5102–5112 (2009). DOI: 10.1007/s10853-009-3545-1.
• I. Levin, J. C. Woicik, A. Llobet, M. G. Tucker, V. Krayzman, J. Pokorny and I. M. Reaney: Displacive ordering transitions in perovskite-like AgNb_1/2Ta_1/2O₃, Chem. Mater. 22, 4987–4995 (2010). DOI: 10.1021/cm101263p.