Recent Research Activities in the Surface Science Lab
Much progress has been made in raising the superconducting transition temperature, to previously unexpected higher values, in certain ceramic materials that are termed as high-temperature superconductors (HTSC). Elemental substitution studies in HTSC have enhanced the understanding of their superconducting and normal state properties. Our research is focused on the electronic structure of some selected substituted HTSC systems. See for more details:
We have also studied the effect of gamma irradiation on the electronic structure of Bi-2223 and Tl-1223. See for more details:
M. Faiz and N.M. Hamdan, J. Elec. Spec. Rel. Phenom. 114-116 (2001) 291 & 427
On going activities include:
1. A study of the effect of annealing conditions on the hole content of Tl-1234.
2. Optimizing synthesis parameters of barium cuprate thin films.
Our concentration is in Metallocene catalysts that have started to shape the future of the olefin polymerization technology. The challenge in this field concerns how to develop an industrially cost- and energy-effective olefin polymerization process. In this regard, heterogenization of the metallocene catalyst precursors plays a key role. Our research addresses some of the problems, which concern the electronic environment resulting from heterogenization. See for more details:
1. M. Atiqullah, M. Faiz, M.N. Akhtar, et al., Surf. Interface Anal. 27 (1999) 728
2. M. Atiqullah, M.N. Akhtar, M. Faiz, et al., Surf. Interface Anal. 38 (2006) 1319
We have also investigated Tungstophosphoric acid and zeolite catalysts using synchrotron-XPS and XANES techniques. See for more details:
1. P.A. Jalil, M. Faiz, N. Tabet, et al., J. Catalysis 217 / 2 (2003) 292
2. P. A. Jalil, N. Tabet, M. Faiz, et al., Applied Catalysis A 257 (2004) 1
3. P.A. Jalil, M.S. Kariapper, M. Faiz, N. Tabet, et al., Applied Catalysis A 290 (2005) 159
X-ray absorption near edge structure (XANES) spectroscopy is a powerful local probe for the electronic structure as well as the atomic structure of materials. It probes the empty energy bands by measuring transitions from core levels, and does not require a crystalline sample. Element specificity and symmetry selection rules are some of the powerful aspects of the technique.
Ferromagnetism in diluted magnetic semiconductors is one of the interesting problems of this century in condensed matter physics. Vanadium-doped ZnO shows ferromagnetism above room temperature upon electron doping. Such a high Curie temperature is appealing for its applications in spintronics devices. Understanding the electronic structure is a prerequisite for understanding the high-temperature ferromagnetism in these materials.
We have used XANES technique to investigate the electronic structure of vanadium-doped ZnO thin films. See for more details:
M. Faiz, N.Tabet, A. Mekki, et al., Thin Solid Films 515 (2006) 1377
XANES is also being used to investigate transition-metal oxide glasses. See for example:
M. Faiz, A. Mekki, et al., J. Elec. Spec. Rel. Phenom. 154 (2007) 60