Raman spectroscopy of Nd-doped BiFeO3 based ceramics and thin films

Dr Hlinka, Head of the Department of Dieletrics at the Academy of Science, Prague, has expressed a strong interest to interact with the Sheffield group and to establish the strongest possible collaboration by becoming a Visiting Professor for a period of 3 months between April-June 2010. This collaboration would hugely advance the burgeoning Raman activity at Sheffield and in doing so improve the knowledge base for the UK in this key area of structural determination. The group of the PI at Sheffield have recently discovered a new AFE, PbZrO3-structured ceramic based on Nd-doped BiFeO3 (BNF). In collaboration with the University of Leeds, the development of thin films of Nd-doped BiFeO3 (BNF) using pulsed laser deposition will shortly begin. The initial aims of this new programme will be to establish whether the AFE structure is retained within the film and whether the structural phase transitions observed in bulk as a function of temperature and composition remain valid. We have established that Raman spectroscopy is sensitive to the structural changes within BNF system but the main problem with such new materials is in the detailed interpretation of the spectra. The key research goals of the Visiting Fellowship are therefore to i) establish the experimental protocols to obtain high quality UV Raman spectra from thin functional films and ii) utilise the vast experience of Dr Hlinka to help interpret the spectra. In addition to the Raman study, the group of the PI will obtain detailed structural information using analytical electron microscopy (EP/F006098/1, S.Miao). In this manner, a complete understanding of the structural changes in BNF thin films will be obtained which will be utilised to interpret the ferroelectric and dielectric behaviour. In addition to these scientific goals, Dr Hlinka will give tutorials on the 'Use of Vibrational Spectroscopy in the Study of Functional Oxides' and will visit several interested groups within the UK Functional Oxide community.

The major impact of this programme is to establish strong funded links between the Academy of Science and the CCL in order to improve our understanding of vibrational spectroscopy and thereby of the structure and symmetry of functional oxides over a range of length scales. This will positively influence many projects within the CCL and enhance our ability to develop and improve functional oxides with the goal of future exploitation. In addition to research, Dr Hlinka will undertake to visit UK groups interested in the study of functional oxides. He will impart his knowledge to these groups and establish new collaborations to pursue on his return to the Czech Republic. He will also give a sequence of tutorials to Ph.D. students at Engineering Materials in the use and interpretation of vibrational spectroscopy to study functional oxides. The schedule of the tutorials will be made known to interested groups who will be encouraged to participate by sending students. The benefit to the UK community of such visits and tutorials is adequately demonstrated in the very positive comments regarding this aspect of the proposal in the letters of support. The purpose of the programme is to establish the necessary protocols to obtain and interpret Raman spectra from BNF ceramics and films. Any commercial product fabricated using BNF is many years away and much groundwork is required. However, the programme will further the efforts at Sheffield to develop BNF and add valuable understanding to drive development of this exciting PbO-free material. Potential devices based on AFE/FE switching are envisaged and efforts are underway to fabricate solid solutions with optimised properties. Should the research culminate in a commercially viable functional thin film material then the potential for exploitation is huge and field changing. In this event, appropriate IPR will be sought but it is not anticipated that patentable technology will emerge directly from this programme.