My research field or area of interest innanotechnology
Previous Research work
Madurai Kamaraj University – Research Centre and PG Department of Physics
Supervisor: Dr. R. Saravanan, The Madura College (Autonomous) Madurai - 625 011, India.
The research was done under the title: “Growth, Structural and Electronic Characterization of some Diluted Magnetic Materials (DMS)”.
Due to the intense interest in the emerging field of spin-based electronics, I focused on exploring the growth and effect of doping magnetic materials such as Manganese, Cobalt and Nickel into the semiconducting materials and study their structural and electronic properties. These materials control electron spins, in addition to charges, in order to transmit information and provide new functionality to semiconductor devices. However, obtaining above room temperature ferromagnetic ordering in these DMSs is essential for their use in spintronics technology, which has been an experimental challenge.
As part of this work, various diluted magnetic materials were grown using high temperature and low temperature techniques. An exhaustive study on the Rietveld analysis was done to analyze the structural properties of the material by X-ray powder diffraction data. The Maximum Entropy method (MEM) and Multipole analysis techniques were used to obtain experimental charge density in the unit cell. The charge density was thoroughly analyzed along the bonding region and the valence regions. The quantitative estimation of spatial charge density along the bonding region reveals information on type of bonding, charge transfer, ionicity, etc. The topological analysis of charge density reveals the orbital arrangements of charge density and also various quantum chemical properties viz, kinetic energy density, Electronic and potential energy density of atoms, Fermi momentum of electrons, the local temperature and entropy. The charge localization and the orbital location were explored from charge density derivatives and the Ferro magnetic charge density disorder was determined via charge density route by the high resolution electron density by MEM (maximum entropy method). Also the local and average structures of doped magnetic materials from atomic pair distribution function (PDF) were studied.
The following materials were studied:
1. Undoped Semiconductors (Si, Ge, GaP, ZnSe, PbSe)
2. Spintronics materials
a. Ge1-xMnx (x = 0.03 and 0.07)
b. Zn1-xCoxO (x = 0.01: Annealing temperature, T = 500°C, 600°C, 700°C, 800°C and 900°C)
c. Zn1-xNixO (x = 0.01, 0.02, 0.03, 0.04 and 0.05)
3. Magnetic compound
d. La0.67Sr0.22Mn1.11-xCoxO3 (x = 0.0, 0.02, 0.05, 0.2 and 0.3).
• Rietveld structural analysis done for both semiconducting and magnetic materials.
• Precise mapping of experimental charge density distribution in a unit crystal.
• Charge density distribution that gives complete information on the spatial distribution, bond strength, bond charges and valence region.
• Experimental crystal properties were quantitatively analyzed.
• MEM approach, multipole analyses were effectively used for exploring experimental information on crystal.
• 10 research papers were published in reputed journals and 1 paper was accepted.
My long term research interests involve growth and characterization of magnetic, semiconductor and oxide nanomaterials such as Mn/Fe/ Ni/ Co doped ZnO, GaSb, GaN, Ge, ZnSe, PbSe, CdS, CdSe, ZnSe and analyze them for various applications in the field of high-density memory, energy materials and examining interventions by X-ray and neutron diffraction measurement so as to understand why they behave in the way they do. Also it is important to understand the spatial arrangement of atoms and charges in a new material for which it is necessary to see the precise experimental charge density distribution in the unit cell. This experimental evidence provides the information accurately which the theoretical models lack. I will extend my specialization in growing thin films (PLD, CVD, MBE) and morphological investigation (XRD, neutron diffraction, SEM, TEM, and AFM), Magnetic properties (SQUID, VSM) to understand the material. This will throw light on the experimental crystal properties that will decide on how the system is going to behave under a given environment. Magnetic ordering and the spin density will be analyzed with the help of neutron diffraction experiments. I would like to collaborate and coordinate my research ideas with my team to lead my success with my team mates.
My previous research study included the detailed quantitative and qualitative analysis of the structural and charge density distribution especially in the valence region which reveals the type of bonding and the charge content involved in it. The profiles of charge density along the bonding direction give enormous information about the bonding and the crystal properties. These properties give quantitative picture on what we can expect out of the solid in terms of its physical and chemical properties. The multipole approach on the charge density redefines the detailed distribution of charges in the core and the valence region as well as in various orbitals. The crystal properties derived out of this give valuable information on the energy of the atom, exchange energy, one electron potential, local Fermi momentum, local internal temperature and entropy and the spatial localization of charge and orbitals and so on.
In conclusion, I feel that continuing my research in nano materials will be the most logical extension of my research pursuits and would be a major step towards achieving my objectives. I would be grateful to you if I’m accorded the opportunity to pursue my post doctoral studies and am sure I would be able to justify your faith in me.
Research Papers Published in Scientific journals
1. XRD analysis of the local structure in diluted magnetic semiconductor Zn1-xNixO
K. S. Syed Ali, R. Saravanan and M. Açıkgöz
Cryst. Res. Technol. 46, No. 1, (2011) 41 – 47.
2. Localized ferromagnetic charge ordering through charge density analysis in nano sized diluted magnetic semiconductor Co2+:ZnO
K. S. Syed Ali, R. Saravanan, S. Israel and M. Açıkgöz
Physica B., 405 (2010) 1763–1769.
3. Local distortion in Co doped LSMO from entropy maximized charge density distribution
K. S. Syed Ali, R. Saravanan, A. V. Pashchenko and V. P. Pashchenko
Journal of Alloys and Compounds., 501 (2010) 307-312.
4. Growth of novel diluted magnetic semiconducting material Ge1-xMnx and X-ray characterization by Maximum Entropy Method (MEM) and Pair Distribution Function (PDF)
K. S. Syed Ali, R. Saravanan and S. Israel
Journal of Crystal Growth., 311 (2009) 1110–1116.
5. Analysis on experimental valence charge density in Germanium at RT and 200 K
S. Israel, K. S. Syed Ali, R.A.J.R. Sheeba and R. Saravanan
Journal of Physics and Chemistry of Solids., 70 (2009) 1185–1194.
6. X-ray analysis of charge density distribution in GaP at 296 and 200K using Multipole and MEM models.
S. Israel, K. S. Syed Ali, R. A. J. R. Sheeba and R. Saravanan
Chinese Journal of Physics., 47 (3) (2009) 378-400.
7. X-Ray Characterization of Ag Impurities in Na1-xAgxCl
Nizarul Hazeen, K. S. Syed Ali, M. Prema Rani and R. Saravanan
Defect and Diffusion Forum., 278 (2008) 33.
8. Electron density distribution and bonding in ZnSe and PbSe using Maximum Entropy Method
K. S. Syed Ali, R. Saravanan, S. Israel, and R. K. Rajaram
Bulletin of material science., 29 (2) (2006) 107- 116.
9. Electron density distribution in Si and Ge using multipole, MEM and pair distribution function
R. Saravanan, K. S. Syed Ali and S. Israel
Pramana journal of physics., 70-4 (2008) 679.
10. Gel growth and X-ray Characterization of ferro-electric single crystals of SrHPO4 and PbHPO4
K. S. Syed Ali, N. Ajeetha and R. Saravanan
Bulletin of pure and applied sciences D: Physics., 21D (2) (2002) 151-157.
Research Papers Communicated
Structural, Magnetic, and Mössbauer Analysis of Dy2Fe17-xNbx Alloys.
Accepted in Transactions on Magnetics
1B. K. Rai, 1S. R. Mishra, 2K. S. Syed Ali, 3S. Khanra and 3K. Ghosh
1The University of Memphis, Memphis, TN 38152, USA; 2Department of Science, Estill High school, Estill, SC 29918, USA; 3The Missouri State University, Springfield, MO 65897, USA
Researchgroup, Institute, University, School, Company name
Madurai Kamaraj University, Madurai, India.
Researchgroup, Institute, Company, University, School webpage
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