| Project leaders: | PD Dr. Steffen Wirth (MPI CPfS Dresden) |
| | Dr. Suja Elisabeth (IISc Bangalore) |
| Funding period: | June 2009 - June 2011 |
Goals:
Strongly correlated transition metal oxides with perovskite-like structure exhibit a host of physical phenomena like metal
insulator transition, superconductivity, magnetic transition and charge/orbital ordering. The main objective of this proposal
is to investigate (1) the relevance of the electronic phase separation to the magneto-transport mechanisms and investigations
of charge ordering in perovskite single crystals and (2) to explore the phase separation scenario in the ordered double
perovskites of the type A
2BB'O
6 (A = alkaline earth ion, B and B' = transition metal ion). Scanning
tunneling microscopy/ spectroscopy (STM/S) will be employed to investigate the phase separation. STS is a powerful tool to
probe quasi-particle density of states (DOS) on an atomic scale with spatial resolution. These experiments should be performed
using good quality single crystals, preferably on the in situ cleaved surfaces in order to distinguish between chemical
inhomogeneity and electronic phase separations.
It is proposed to grow single crystals of these multi-valent perovskites in the crystal growth laboratory of Indian Institute
of Science (IISc) by the Indian investigator and the associated research team. The single crystals will be grown using flux
method or float zone technique. After preliminary characterization at IISc, these crystals will be investigated in detail at
the Max-Planck-Institut für Chemische Physik fester Stoffe, (MPI CPfS) Dresden, using STM/S. This will provide a direct access
for the investigation of phase separation, charge/orbital ordering, long range charge density wave modulation, and defect studies
that influence magnetoresistance in perovskites. Since many layered systems have transition temperatures close to room temperature,
we will explore potential materials for spintronic applications.